文章
Dummer. ゛☀
2017年09月19日
Crassula ovata also known as Jade Plant is a succulent often used as a houseplant. This well-behaved plant blends into the landscape in USDA hardiness zones 9 through 11, where it thrives on neglect. Few pests or diseases affect Jade Plant, but when white powdery mold appears on its leaves, it is often the result of environmental problems. If you have white mold on your Jade Plant, you’re more likely dealing with powdery mildew. True to their easy-care nature, though, Jade Plants bounce back from powdery mildew once it is properly treated. 
Powdery Mildew
Powdery mildew is caused by several different fungi that grow in a thin layer on plant tissues. In perennial plants such as Jade Plant, the fungal bodies can overwinter in buds, re-emerging when conditions are ideal for their growth. Spores are often distributed by the wind to new, uninfected plants or spread in greenhouses from plant to plant. Temperatures between 60 and 80 degrees Fahrenheit (16 and 27 degrees Celsius) are required for germination, along with a relative humidity above 90 percent. Standing water on leaves is not necessary and can actually inhibit spore germination in some cases. Standing water encourages other fungal growth, through, so it should be discouraged.
Damage
Powdery mildew begins as a white powdery coating on the plant’s leaf surfaces, but soon spreads, penetrating plant tissues and sending out spores. Emerging vegetation may be dwarfed or distorted and covered in white mildew. Jade Plants also develop corky brown lesions where powdery mildew is taking hold. If not addressed, this mildew will spread farther, resulting in leaf drop and the eventual death of the Jade Plant.
Cultural Control
Cultural control is effective for powdery mildew. Plant Jade Plants in full sun and trim them to encourage better air circulation. Reduce watering if the plant’s soil is often moist; always allow the soil to dry before watering Jade Plants. Powdery mildew spores can be killed with water, but be careful to wet the plant early in the day so that it can dry completely. Stop misting house Jade Plants, instead water them at the base of the plant since humidity around the plant is what encourages the growth of powdery mildew.
Chemical Control
Several chemicals are available for chronically infested plants or those that are victims of environmental conditions beyond the control of the gardener. Test a safer pesticide such as horticultural or neem oil on a small spot on your Jade Plant before spraying the entire plant thoroughly. If an outside Jade Plant yellows or shows signs of sunburn, utilize a sunshade until signs of powdery mildew are gone to prevent serious damage. Never apply horticultural oils when temperatures are above 90 degrees Fahrenheit (32 degrees Celsius).
Powdery Mildew
Powdery mildew is caused by several different fungi that grow in a thin layer on plant tissues. In perennial plants such as Jade Plant, the fungal bodies can overwinter in buds, re-emerging when conditions are ideal for their growth. Spores are often distributed by the wind to new, uninfected plants or spread in greenhouses from plant to plant. Temperatures between 60 and 80 degrees Fahrenheit (16 and 27 degrees Celsius) are required for germination, along with a relative humidity above 90 percent. Standing water on leaves is not necessary and can actually inhibit spore germination in some cases. Standing water encourages other fungal growth, through, so it should be discouraged.
Damage
Powdery mildew begins as a white powdery coating on the plant’s leaf surfaces, but soon spreads, penetrating plant tissues and sending out spores. Emerging vegetation may be dwarfed or distorted and covered in white mildew. Jade Plants also develop corky brown lesions where powdery mildew is taking hold. If not addressed, this mildew will spread farther, resulting in leaf drop and the eventual death of the Jade Plant.
Cultural Control
Cultural control is effective for powdery mildew. Plant Jade Plants in full sun and trim them to encourage better air circulation. Reduce watering if the plant’s soil is often moist; always allow the soil to dry before watering Jade Plants. Powdery mildew spores can be killed with water, but be careful to wet the plant early in the day so that it can dry completely. Stop misting house Jade Plants, instead water them at the base of the plant since humidity around the plant is what encourages the growth of powdery mildew.
Chemical Control
Several chemicals are available for chronically infested plants or those that are victims of environmental conditions beyond the control of the gardener. Test a safer pesticide such as horticultural or neem oil on a small spot on your Jade Plant before spraying the entire plant thoroughly. If an outside Jade Plant yellows or shows signs of sunburn, utilize a sunshade until signs of powdery mildew are gone to prevent serious damage. Never apply horticultural oils when temperatures are above 90 degrees Fahrenheit (32 degrees Celsius).
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文章
Dummer. ゛☀
2017年09月19日
Several viruses infect tomatoes and peppers. The two most common are tobacco mosaic virus and cucumber mosaic virus.
Symptoms and Diagnosis
Symptoms vary depending upon the virus and strain, the plant, time of year, and environmental conditions. The most common symptoms include leaf mottling; puckering or curling; stem and petiole streaking; rough, deformed or spotted fruit; stunted plants; and blossom and fruit drop. Some viruses cause the leaves of tomatoes to become fernlike or develop a thin "shoestring" appearance. Symptoms may be confused with herbicide damage.
Life Cycle
Viruses have no active way of penetrating plant parts. They rely upon mechanical wounds, infected seeds, and being carried in the bodies of insects for transmission. The virus can also be present in tobacco and transmitted to plants by the hands of people who smoke. Once inside the plant cells, the virus replicates. The virus does not usually kill the plant and takes over the metabolic processes of the leaf, resulting in abnormal cell functioning and growth.
Integrated Pest Management Strategies
1. Remove diseased plants. Once a plant is infected, there are no practical field methods of curing the plant of the virus. Remove infected plants as soon as they are noticed to reduce the chance of spreading the disease.
2. Follow strict sanitation. Persons handling plants must refrain from the use of tobacco or risk infecting the plants. Remove weeds in the area that could harbor the virus.
3. Control insects. Because insects, especially aphids, vector cucumber mosaic, make every effort to keep insects under control using sticky traps or insecticides.
4. Plant resistant varieties. In subsequent years, plant varieties that are resistant to the most common viruses. Look for varieties that are marked TMV or CMV after the variety name.
Symptoms and Diagnosis
Symptoms vary depending upon the virus and strain, the plant, time of year, and environmental conditions. The most common symptoms include leaf mottling; puckering or curling; stem and petiole streaking; rough, deformed or spotted fruit; stunted plants; and blossom and fruit drop. Some viruses cause the leaves of tomatoes to become fernlike or develop a thin "shoestring" appearance. Symptoms may be confused with herbicide damage.
Life Cycle
Viruses have no active way of penetrating plant parts. They rely upon mechanical wounds, infected seeds, and being carried in the bodies of insects for transmission. The virus can also be present in tobacco and transmitted to plants by the hands of people who smoke. Once inside the plant cells, the virus replicates. The virus does not usually kill the plant and takes over the metabolic processes of the leaf, resulting in abnormal cell functioning and growth.
Integrated Pest Management Strategies
1. Remove diseased plants. Once a plant is infected, there are no practical field methods of curing the plant of the virus. Remove infected plants as soon as they are noticed to reduce the chance of spreading the disease.
2. Follow strict sanitation. Persons handling plants must refrain from the use of tobacco or risk infecting the plants. Remove weeds in the area that could harbor the virus.
3. Control insects. Because insects, especially aphids, vector cucumber mosaic, make every effort to keep insects under control using sticky traps or insecticides.
4. Plant resistant varieties. In subsequent years, plant varieties that are resistant to the most common viruses. Look for varieties that are marked TMV or CMV after the variety name.
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文章
Dummer. ゛☀
2017年09月19日
Viral infections can reduce plant vigor by disrupting cellular functioning, but do not commonly kill plants. Tobacco mosaic is one of the most highly persistent tomato diseases because it can remain viable without a host for many years and it is able to withstand high heat. The virus is spread primarily by mechanical methods. Gardeners can contaminate their hands when they touch tobacco products or infected plants and weeds and spread the virus to healthy plants.
Symptoms and Diagnosis
Tobacco mosaic virus is not as distinct as other viruses, but yellow-green mottling on leaves is the most characteristic symptom of the disease. Infected plants have stunted growth, and flowers and leaflets may be curled, distorted, and smaller than normal in size. Open blooms may have brown streaks through them. Yellow, chlorotic spotting is characteristic of pepper plants that are infected.
Life Cycle
Tobacco mosaic virus survives on infected seeds, plant debris, and even clothing for months or years. The virus enters plants through wounds sustained in transplanting or pruning. It spreads rapidly once it is in the host. The virus can remain viable for years on dried plant debris and is extremely tolerant of very high temperatures. Tobacco products are the most common source of inoculum; smokers can infect plants by handling them. The virus is not spread by aphids.
Integrated Pest Management Strategies
1. Remove and destroy infected plants. Pull plants with mosaic symptoms immediately. Remove the debris from the garden area and bury them if possible.
2. Keep your garden weed-free. Some weed may be harboring the virus. These represent sources of inoculum.
3. Always wash your hands thoroughly and disinfect tools. Before handling plants, wash with soap and water, especially if you're a smoker.
4. Plant resistant varieties of tomato. Suggested varieties include: ‘Big Pick’, ‘Celebrity’, ‘President’, and ‘Park's Extra Early Hybrid’. Other resistant varieties will be labeled TMV resistant.
Symptoms and Diagnosis
Tobacco mosaic virus is not as distinct as other viruses, but yellow-green mottling on leaves is the most characteristic symptom of the disease. Infected plants have stunted growth, and flowers and leaflets may be curled, distorted, and smaller than normal in size. Open blooms may have brown streaks through them. Yellow, chlorotic spotting is characteristic of pepper plants that are infected.
Life Cycle
Tobacco mosaic virus survives on infected seeds, plant debris, and even clothing for months or years. The virus enters plants through wounds sustained in transplanting or pruning. It spreads rapidly once it is in the host. The virus can remain viable for years on dried plant debris and is extremely tolerant of very high temperatures. Tobacco products are the most common source of inoculum; smokers can infect plants by handling them. The virus is not spread by aphids.
Integrated Pest Management Strategies
1. Remove and destroy infected plants. Pull plants with mosaic symptoms immediately. Remove the debris from the garden area and bury them if possible.
2. Keep your garden weed-free. Some weed may be harboring the virus. These represent sources of inoculum.
3. Always wash your hands thoroughly and disinfect tools. Before handling plants, wash with soap and water, especially if you're a smoker.
4. Plant resistant varieties of tomato. Suggested varieties include: ‘Big Pick’, ‘Celebrity’, ‘President’, and ‘Park's Extra Early Hybrid’. Other resistant varieties will be labeled TMV resistant.
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文章
Dummer. ゛☀
2017年09月19日
Root-knot nematodes are microscopic, plant-parasitic roundworms in the genus, Meloidogyne. Normally they exist in sandy soil in hot climates or short winters, but they have spread to our region as well. In Missouri alone 40 species of parasitic nematodes exist. About 2000 plants are susceptible to infection by these nematodes, and they can cause global crop loss. Root-knot nematode larvae infect plant roots that drain the plant’s ability to take up water and sufficient nutrients. Because of their microscopic size the nematodes go unnoticed until serious symptoms appear. The pathogenic nematodes can allow entrances for root rots, and wilts. They can also transmit viral diseases.
Symptoms and Diagnosis
A plant infected with root-knot nematodes often exhibits the same signs of nutrient deficiency. It may be stunted, yellowed, or wilted, and can lead to premature death of the plant. Below the ground, the roots of the plant are swollen or knotted with root galls, and unless a plant is removed from the soil to examine the roots, the cause of the poor plant growth remains undetected. The appearance of the galls on the roots can be confused with nitrogen-fixing nodules common in the legume family. However it is easy to distinguish between them, as the nitrogen nodules can be easily rubbed off while the nematode galls cannot be removed.
Life Cycle
The root-knot nematode is parthenogenic, that is a single female can reproduce without males and a new generation can occur every 28 days if conditions are ideal. Inside the gall, the enlarged female appears as a shiny white body, the size of a pinhead. She deposits 300 to 500 eggs in a protective jelly-like material. These glistening white to yellow egg masses are present on the root surfaces. Juveniles emerge from the eggs in the soil and penetrate between and through cells at the center of the root, usually near the growing tip. These larvae actively feed and remain at this same site. The juvenile stage can over-winter even under very unfavorable conditions. New adult nematodes develop from the larvae and start the cycle again.
Integrated Pest Management Strategies
1. Never buy or plant any stunted-yellowed plants. When a new plant’s roots are examined and its roots contain root knots that will not easily rub off, do not plant it. If someone gives you a division of their plant whose roots contain these root-knots, never add it to your garden because it will contaminate all of your healthy plants with the nematodes.
2. Keep plants healthy and avoid stressing plants and water plants during periods of high temperatures and drought. Also keep other insect pests and fungal diseases under control. Control weeds as they can act as hosts to these nematodes. Keep tools clean.
3. ;Rotate crops, planting nematode resistant plants when possible. It may take 3-5 years to kill off these nematodes before replanting the same plant.
4. Destroy any plants you discover that are infested with root-knot nematodes and don’t compost them. Replace all the soil before adding a new plant to this area.
5. Soil solarization has demonstrated some success in eliminating root-knot nematodes. Thoroughly moisten the soil and cover with clear plastic in full sun during the hottest months of the year. The soil must maintain these high temperatures for a period of at least 4-6 weeks to be effective. Re-moisten the soil under the plastic if it dries out.
6. No chemical controls are advised for home gardeners. Some restricted use chemicals are available for commercial, licensed applicators.
Symptoms and Diagnosis
A plant infected with root-knot nematodes often exhibits the same signs of nutrient deficiency. It may be stunted, yellowed, or wilted, and can lead to premature death of the plant. Below the ground, the roots of the plant are swollen or knotted with root galls, and unless a plant is removed from the soil to examine the roots, the cause of the poor plant growth remains undetected. The appearance of the galls on the roots can be confused with nitrogen-fixing nodules common in the legume family. However it is easy to distinguish between them, as the nitrogen nodules can be easily rubbed off while the nematode galls cannot be removed.
Life Cycle
The root-knot nematode is parthenogenic, that is a single female can reproduce without males and a new generation can occur every 28 days if conditions are ideal. Inside the gall, the enlarged female appears as a shiny white body, the size of a pinhead. She deposits 300 to 500 eggs in a protective jelly-like material. These glistening white to yellow egg masses are present on the root surfaces. Juveniles emerge from the eggs in the soil and penetrate between and through cells at the center of the root, usually near the growing tip. These larvae actively feed and remain at this same site. The juvenile stage can over-winter even under very unfavorable conditions. New adult nematodes develop from the larvae and start the cycle again.
Integrated Pest Management Strategies
1. Never buy or plant any stunted-yellowed plants. When a new plant’s roots are examined and its roots contain root knots that will not easily rub off, do not plant it. If someone gives you a division of their plant whose roots contain these root-knots, never add it to your garden because it will contaminate all of your healthy plants with the nematodes.
2. Keep plants healthy and avoid stressing plants and water plants during periods of high temperatures and drought. Also keep other insect pests and fungal diseases under control. Control weeds as they can act as hosts to these nematodes. Keep tools clean.
3. ;Rotate crops, planting nematode resistant plants when possible. It may take 3-5 years to kill off these nematodes before replanting the same plant.
4. Destroy any plants you discover that are infested with root-knot nematodes and don’t compost them. Replace all the soil before adding a new plant to this area.
5. Soil solarization has demonstrated some success in eliminating root-knot nematodes. Thoroughly moisten the soil and cover with clear plastic in full sun during the hottest months of the year. The soil must maintain these high temperatures for a period of at least 4-6 weeks to be effective. Re-moisten the soil under the plastic if it dries out.
6. No chemical controls are advised for home gardeners. Some restricted use chemicals are available for commercial, licensed applicators.
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文章
Dummer. ゛☀
2017年09月19日
If your tomato plants yellow and wilt on one side of the plant or one side of a leaf, they may have Fusarium wilt. Fusarium wilt on tomatoes is caused by Fusarium oxysporumsp. lycopersici. It is a soilborn fungus that is found throughout the United States, especially in warm regions of the country. The organism is specific for tomato and is very longlived in all regions of the United States. The disease develops more quickly in soils that are high in nitrogen and low in potassium. In addition, plants grown in sandy soils tend to contract this disease more often.
Symptoms and Diagnosis
Fusarium often causes yellowing on one side of the plant or leaf. Yellowing begins with the older, bottom leaves, followed by wilting, browning, and defoliation. Growth is typically stunted, and little or no fruit develops. Brown, vascular tissue can be found when the infected stem is cut at its base. Infected plants often die before maturing.
Life Cycle
Fusarium fungi survive in the soil or associated with plant debris for up to ten years. Disease development is favored by warm soil temperatures, and symptoms are most prevalent when temperatures range from 80–90 degrees F. The fungi enter the plants through their roots and are then spread throughout the plant by the plant's water-conducting vessels.
Integrated Pest Management Strategies
1. Plant resistant varieties. These varieties are labeled VF and include cultivars such as ‘Spring Giant’, ‘Burpee VF’, ‘Supersonic’, ‘Celebrity’, ‘Manalucie’, ‘Better Boy’, and ‘Small Fry’.
2. Remove infected plants from the garden. Removal of infected plants will help limit the disease's spread. Soil sterilization or fumigation will eliminate wilt fungi from the soil but are impractical for home gardeners. Soil replacement should be considered.
3. Avoid over-application of high nitrogen fertilizers. High soil nitrogen levels accompanied by low potassium levels can increase susceptibility to the fungus. Use a soil test to determine potassium levels and other nutrient deficiencies.
4. Avoid activity in wet plantings. Movement of wet soil from place to place via shoes or tools will spread the disease.
5. Sanitize stakes and tomato cages at the end of the season. Avoid using soil-encrusted tools and supports season after season. A thorough cleaning with water will reduce most risk of transmitting the disease.
6. For four years, do not plant solanaceous plants in the area where infection occurred. Tomato, potato, pepper, and eggplant are all susceptible to the disease and may allow its survival year after year in the same planting area.
Symptoms and Diagnosis
Fusarium often causes yellowing on one side of the plant or leaf. Yellowing begins with the older, bottom leaves, followed by wilting, browning, and defoliation. Growth is typically stunted, and little or no fruit develops. Brown, vascular tissue can be found when the infected stem is cut at its base. Infected plants often die before maturing.
Life Cycle
Fusarium fungi survive in the soil or associated with plant debris for up to ten years. Disease development is favored by warm soil temperatures, and symptoms are most prevalent when temperatures range from 80–90 degrees F. The fungi enter the plants through their roots and are then spread throughout the plant by the plant's water-conducting vessels.
Integrated Pest Management Strategies
1. Plant resistant varieties. These varieties are labeled VF and include cultivars such as ‘Spring Giant’, ‘Burpee VF’, ‘Supersonic’, ‘Celebrity’, ‘Manalucie’, ‘Better Boy’, and ‘Small Fry’.
2. Remove infected plants from the garden. Removal of infected plants will help limit the disease's spread. Soil sterilization or fumigation will eliminate wilt fungi from the soil but are impractical for home gardeners. Soil replacement should be considered.
3. Avoid over-application of high nitrogen fertilizers. High soil nitrogen levels accompanied by low potassium levels can increase susceptibility to the fungus. Use a soil test to determine potassium levels and other nutrient deficiencies.
4. Avoid activity in wet plantings. Movement of wet soil from place to place via shoes or tools will spread the disease.
5. Sanitize stakes and tomato cages at the end of the season. Avoid using soil-encrusted tools and supports season after season. A thorough cleaning with water will reduce most risk of transmitting the disease.
6. For four years, do not plant solanaceous plants in the area where infection occurred. Tomato, potato, pepper, and eggplant are all susceptible to the disease and may allow its survival year after year in the same planting area.
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文章
Dummer. ゛☀
2017年09月19日
Blossom-end rot is a physiological disorder of tomatoes and peppers. It is a disturbance in the normal physiology of the plant. Because it is not caused by an insect or disease organism, fungicidal and insecticidal sprays are not effective in controlling the problem.
Symptoms and Diagnosis
An early symptom of blossom-end rot is a light tan patch on the blossom end of the green fruit. Over time the area turns dark brown or black and may become sunken or leathery. Fruit which is one-third to one-half developed is most commonly affected. Sometimes an internal black rot will develop in the center of the fruit with little or no external symptoms. Parts of the fruit not affected by blossom-end rot may be eaten.
Causes of Blossom-End Rot
The most common cause of blossom-end rot is fluctuating soil moisture. Moisture plays an important role in calcium uptake in the plant. When a dry period follows adequate moisture, calcium uptake can be reduced. Root damage due to deep cultivation or burning from improper fertilization can also restrict calcium uptake. Excessive applications of fertilizer containing ammonia can also result in symptoms. Less frequently, an actual deficiency of calcium in the soil may cause this rot. This is rarely the case in St. Louis.
Integrated Pest Management Strategies
1. Maintain even soil moisture. Water regularly during dry periods and mulch plants with a 3–4 inch layer of organic material to help hold in soil moisture.
2. Avoid deep cultivation too near plants.
3. Modify your fertilizing practices. Use a fertilizer high in superphosphate and low in nitrogen. When adding nitrogen, use calcium nitrate rather than ammonia or urea forms.
4. Get a soil test. If the above methods do not correct the problem, get a soil test and maintain soil pH at 6.5 to 7.
5. As a last resort, use a foliar spray of calcium chloride. Do not spray too often or in excessive amounts.
6. Tomatoes in container. For tomatoes grown in containers, apply a fertilizer specifically formulated for tomatoes. The fertilizer must contain micronutrients including calcium.
Symptoms and Diagnosis
An early symptom of blossom-end rot is a light tan patch on the blossom end of the green fruit. Over time the area turns dark brown or black and may become sunken or leathery. Fruit which is one-third to one-half developed is most commonly affected. Sometimes an internal black rot will develop in the center of the fruit with little or no external symptoms. Parts of the fruit not affected by blossom-end rot may be eaten.
Causes of Blossom-End Rot
The most common cause of blossom-end rot is fluctuating soil moisture. Moisture plays an important role in calcium uptake in the plant. When a dry period follows adequate moisture, calcium uptake can be reduced. Root damage due to deep cultivation or burning from improper fertilization can also restrict calcium uptake. Excessive applications of fertilizer containing ammonia can also result in symptoms. Less frequently, an actual deficiency of calcium in the soil may cause this rot. This is rarely the case in St. Louis.
Integrated Pest Management Strategies
1. Maintain even soil moisture. Water regularly during dry periods and mulch plants with a 3–4 inch layer of organic material to help hold in soil moisture.
2. Avoid deep cultivation too near plants.
3. Modify your fertilizing practices. Use a fertilizer high in superphosphate and low in nitrogen. When adding nitrogen, use calcium nitrate rather than ammonia or urea forms.
4. Get a soil test. If the above methods do not correct the problem, get a soil test and maintain soil pH at 6.5 to 7.
5. As a last resort, use a foliar spray of calcium chloride. Do not spray too often or in excessive amounts.
6. Tomatoes in container. For tomatoes grown in containers, apply a fertilizer specifically formulated for tomatoes. The fertilizer must contain micronutrients including calcium.
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文章
Dummer. ゛☀
2017年09月19日
Crown gall is a plant disease caused by the soil-inhabiting bacterium, Agrobacterium tumefaciens. The bacterium causes abnormal growths or galls on roots, twigs, and branches of euonymus and other shrubs primarily in the rose family. The bacterium stimulates the rapid growth of plant cells that results in the galls. In addition to being unsightly, the galls weaken and stunt the growth of the plant. Although galls can disrupt the flow of water and nutrients up the roots and branches, they usually do not cause total plant death. The disease can spread to other susceptible plants through contaminated soil and tools. Most chemical treatments are not effective.
The galls on forsythia, viburnum, highbush blueberry, American elm, hickory, maple, oak, and privet are believed to be caused by a fungus, Phomopsis sp. Since its cultural controls are the same as for bacterial crown gall, both are treated together herein. Chemical treatments, however, will differ. Chemical treatments for both are of very limited value to the home gardener. Only those relating to bacterial crown gall have been addressed.
Symptoms and Diagnosis
Galls are most commonly found near ground level on the roots and lower branches of the plants. As the galls enlarge, they become woody and hard. The outer layer turns brown and corky. The plant may be weakened and stunted with some branch or tip dieback. Symptoms may not develop immediately after infection. Galls grow most rapidly during the warm months of the year.
Life Cycle
Crown gall forming bacteria inhabit the soil and survive for many years. The bacterium can initially be brought in on the roots of infected plants. It then spreads by soil and water movement or contaminated pruning tools. Bacteria enter the plant through wounds possibly caused by chewing insects, cultivation damage, or from grafting and pruning tools. The crown gall bacterium has been known to survive more than two years in the soil in the absence of susceptible plants. It can live for several years in decomposing galls buried in the soil. Crown gall is likely to be more serious in limed soil than in acid soils so soil pH could be important in limiting the disease.
Integrated Pest Management Strategies
1. Prune out infected material. Crown gall cannot be eliminated from a shrub even though the infected plant may live for many years. To improve the appearance of the plant, prune out and destroy infected stems below the galled area. Sterilize the pruning shears after each cut with a mixture of one part bleach to nine parts water.
2. Destroy infected plants. Destroy the infected plant. The bacterium will remain in the soil so it is important to plant a resistant plant species. If the same species needs to be planted in the area, remove and replace the soil or consider soil sterilization.
3. Sterilize the soil. Soils known to be infected with crown gall bacteria can be sterilized using chemicals, heat, or antibiotics. This is not practical for most home gardeners. A biological control has been introduced using a bacterium, Agrobacterium radiobactor strain 84. This bacterium was discovered to be antagonistic to crown gall bacterium. It is available for use as a preplant treatment by dipping nursery stock in a suspension of the live bacteria in water.
4. Exclude the problem. When purchasing forsythia and euonymus plants, inspect them carefully for signs of galls. Do not purchase plants that show gall-forming symptoms.
5. Replant with a more resistant plant species. The following plants recommended by the University of Illinois show greater resistance to bacterial crown gall: barberry, hornbeam, true cedars, ginkgo, golden raintree, tulip tree, mahonia, spruce, linden, boxwood, catalpa, beech, holly, larch, magnolia, black gum, pine, Douglas fir, bald cypress, hemlock, birch, firethorn, redbud, smoke tree, sweet gum, deutzia, serviceberry, yellowwood, yew, and zelkova.
The galls on forsythia, viburnum, highbush blueberry, American elm, hickory, maple, oak, and privet are believed to be caused by a fungus, Phomopsis sp. Since its cultural controls are the same as for bacterial crown gall, both are treated together herein. Chemical treatments, however, will differ. Chemical treatments for both are of very limited value to the home gardener. Only those relating to bacterial crown gall have been addressed.
Symptoms and Diagnosis
Galls are most commonly found near ground level on the roots and lower branches of the plants. As the galls enlarge, they become woody and hard. The outer layer turns brown and corky. The plant may be weakened and stunted with some branch or tip dieback. Symptoms may not develop immediately after infection. Galls grow most rapidly during the warm months of the year.
Life Cycle
Crown gall forming bacteria inhabit the soil and survive for many years. The bacterium can initially be brought in on the roots of infected plants. It then spreads by soil and water movement or contaminated pruning tools. Bacteria enter the plant through wounds possibly caused by chewing insects, cultivation damage, or from grafting and pruning tools. The crown gall bacterium has been known to survive more than two years in the soil in the absence of susceptible plants. It can live for several years in decomposing galls buried in the soil. Crown gall is likely to be more serious in limed soil than in acid soils so soil pH could be important in limiting the disease.
Integrated Pest Management Strategies
1. Prune out infected material. Crown gall cannot be eliminated from a shrub even though the infected plant may live for many years. To improve the appearance of the plant, prune out and destroy infected stems below the galled area. Sterilize the pruning shears after each cut with a mixture of one part bleach to nine parts water.
2. Destroy infected plants. Destroy the infected plant. The bacterium will remain in the soil so it is important to plant a resistant plant species. If the same species needs to be planted in the area, remove and replace the soil or consider soil sterilization.
3. Sterilize the soil. Soils known to be infected with crown gall bacteria can be sterilized using chemicals, heat, or antibiotics. This is not practical for most home gardeners. A biological control has been introduced using a bacterium, Agrobacterium radiobactor strain 84. This bacterium was discovered to be antagonistic to crown gall bacterium. It is available for use as a preplant treatment by dipping nursery stock in a suspension of the live bacteria in water.
4. Exclude the problem. When purchasing forsythia and euonymus plants, inspect them carefully for signs of galls. Do not purchase plants that show gall-forming symptoms.
5. Replant with a more resistant plant species. The following plants recommended by the University of Illinois show greater resistance to bacterial crown gall: barberry, hornbeam, true cedars, ginkgo, golden raintree, tulip tree, mahonia, spruce, linden, boxwood, catalpa, beech, holly, larch, magnolia, black gum, pine, Douglas fir, bald cypress, hemlock, birch, firethorn, redbud, smoke tree, sweet gum, deutzia, serviceberry, yellowwood, yew, and zelkova.
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文章
Dummer. ゛☀
2017年09月19日
Root weevils feed on a variety of plants, including needled and broad-leaved evergreens, deciduous and herbaceous plants, and several important food crops. Adults feed on leaves of the host plant and larvae feed on the roots. Host plants differ, but similarities in habits, life cycles, and management practices permit them to be addressed as a group.
Representative root weevil species:
Black vine weevil (Otiorhynchus sulcatus) syn: taxus weevil. Host plants: yews, hemlocks, rhododendrons, several other broad-leaved evergreens, and greenhouse plants such as asters, cyclamens, and impatiens. (see IPM sheet: Black Vine Weevil)
Carrot weevil (Listronatus oregonensis) Host plants: carrots and other vegetables. More common in the east.
Strawberry root weevil (Otiorhynchus ovatus) Host plant: strawberries.
New York weevil (Ithycerus noveboracensis) Eastern U.S., west to Nebraska and Texas. Host plants: Hickory, oak, beech.
Sweet potato weevil (Cylas formicarius elegantulus) syn: sweet potato root borer. Introduced species occurring more commonly in the south U.S. Host plant: sweet potato. Probably not here yet, but with global warming, it's probably only a matter of time.
Symptoms and Diagnosis
Starting in spring, emerging root weevil adults feed on the leaves of host plants, notching the leaf edges quite distinctively. The adult weevils rest during the day and feed on the leaf margins after sundown. Conifer needle damage is less evident than that on broad leafed plants. Needles may be severed and dropped from the tree. Adults feeding on new growth may result in sparse foliage.
Although top feeding of the adults is the most conspicuous damage, root feeding of the larvae does the most damage as they chew and girdle roots of their various host plants. Root weevil larvae can be devastating to conifer seedlings. Woody plant seedlings and propagation cuttings are at risk from both root and top feeding. Injured plants may develop a greenish-yellow cast that does not respond to fertilization and watering. Container grown plants may be severely stunted or killed. Injured plants may die suddenly.
Carrots and sweet potatoes affected by root feeders are not commercially viable and mostly not fit for the table. Damage to roots and crowns can weaken, stunt, and kill strawberry plants.
Life Cycle
Outdoors, there is one weevil generation per year. Greenhouse conditions may permit two generations annually. Many, if not most, root weevils dispense with the annoyance and inconvenience of males, producing the eggs of the next generation by means of parthenogenensis. Females deposit eggs in soil and debris near the host plant, starting usually in mid-summer, and continuing well into the fall, laying hundreds of eggs. Eggs hatch in about 10 days and the larvae move into the soil, feeding on root hairs and roots. Older larvae may girdle entire stems. Larvae are legless, c-shaped, and cream colored with brown heads. They spend the winter in the soil and continue their development in the spring as the soil warms. This second feeding period is the most destructive. Later in the spring, the mature larvae pupate in the soil and soon emerge as adult weevils. After several weeks of feeding on the leaves of host plants, adults begin the egg laying cycle again. Some adult weevils will not expire in the fall but will over-winter. These over-wintering adults will begin egg laying earlier than those adults just emerging from the pupae state.
Integrated Pest Management Strategies
(Control efforts may be directed towards both larvae and adults.)
1. Use nematodes can be applied as a soil drench to control root weevil larvae. Two commercially available cultures, Steinernema and Heterorhabditis are effective. Timing is critical. Apply nematodes when soil temperature is 55°F and soil is moist. Pull back any mulch, apply the nematodes and replace the mulch.
2. Apply pesticides. Chemical stomach poisons applied to the foliage are effective. Pesticides registered for use include acephate (Orthene), azadirachtin (Bio-Neem), imidacloprid (Merit), cyfluthrin and endosulfan (Thiodan). Pesticides should be applied to the foliage thoroughly, allowing excess to run off into the soil beneath the plant. Repeat at least twice at two week intervals. Pesticides appropriate for ornamentals may not be safe for vegetable and fruit crops. Read and follow the label instructions on all pesticides.
3. Use sticky substances. Adult weevils emerge from soil and debris at night and climb the plants to eat. Lower trunks of host plants may be wrapped with a four inch band of masking tape and the product Tanglewood applied to the taped surface. Check for buildup of dead insects regularly, and refresh as needed.
4. Try an organic solution. Weevils are attracted to water and may be trapped in shallow pans inset into the soil near affected host plants. Products that contain the organically derived insecticide spinosad are also labeled for leaf-feeding beetles on a wide variety of plants, and may be worth a try. Diatomaceous earth dusted at the base of affected plants is useful. In serious infestations, the lower sides of stems and leaf undersides should also be dusted.
Representative root weevil species:
Black vine weevil (Otiorhynchus sulcatus) syn: taxus weevil. Host plants: yews, hemlocks, rhododendrons, several other broad-leaved evergreens, and greenhouse plants such as asters, cyclamens, and impatiens. (see IPM sheet: Black Vine Weevil)
Carrot weevil (Listronatus oregonensis) Host plants: carrots and other vegetables. More common in the east.
Strawberry root weevil (Otiorhynchus ovatus) Host plant: strawberries.
New York weevil (Ithycerus noveboracensis) Eastern U.S., west to Nebraska and Texas. Host plants: Hickory, oak, beech.
Sweet potato weevil (Cylas formicarius elegantulus) syn: sweet potato root borer. Introduced species occurring more commonly in the south U.S. Host plant: sweet potato. Probably not here yet, but with global warming, it's probably only a matter of time.
Symptoms and Diagnosis
Starting in spring, emerging root weevil adults feed on the leaves of host plants, notching the leaf edges quite distinctively. The adult weevils rest during the day and feed on the leaf margins after sundown. Conifer needle damage is less evident than that on broad leafed plants. Needles may be severed and dropped from the tree. Adults feeding on new growth may result in sparse foliage.
Although top feeding of the adults is the most conspicuous damage, root feeding of the larvae does the most damage as they chew and girdle roots of their various host plants. Root weevil larvae can be devastating to conifer seedlings. Woody plant seedlings and propagation cuttings are at risk from both root and top feeding. Injured plants may develop a greenish-yellow cast that does not respond to fertilization and watering. Container grown plants may be severely stunted or killed. Injured plants may die suddenly.
Carrots and sweet potatoes affected by root feeders are not commercially viable and mostly not fit for the table. Damage to roots and crowns can weaken, stunt, and kill strawberry plants.
Life Cycle
Outdoors, there is one weevil generation per year. Greenhouse conditions may permit two generations annually. Many, if not most, root weevils dispense with the annoyance and inconvenience of males, producing the eggs of the next generation by means of parthenogenensis. Females deposit eggs in soil and debris near the host plant, starting usually in mid-summer, and continuing well into the fall, laying hundreds of eggs. Eggs hatch in about 10 days and the larvae move into the soil, feeding on root hairs and roots. Older larvae may girdle entire stems. Larvae are legless, c-shaped, and cream colored with brown heads. They spend the winter in the soil and continue their development in the spring as the soil warms. This second feeding period is the most destructive. Later in the spring, the mature larvae pupate in the soil and soon emerge as adult weevils. After several weeks of feeding on the leaves of host plants, adults begin the egg laying cycle again. Some adult weevils will not expire in the fall but will over-winter. These over-wintering adults will begin egg laying earlier than those adults just emerging from the pupae state.
Integrated Pest Management Strategies
(Control efforts may be directed towards both larvae and adults.)
1. Use nematodes can be applied as a soil drench to control root weevil larvae. Two commercially available cultures, Steinernema and Heterorhabditis are effective. Timing is critical. Apply nematodes when soil temperature is 55°F and soil is moist. Pull back any mulch, apply the nematodes and replace the mulch.
2. Apply pesticides. Chemical stomach poisons applied to the foliage are effective. Pesticides registered for use include acephate (Orthene), azadirachtin (Bio-Neem), imidacloprid (Merit), cyfluthrin and endosulfan (Thiodan). Pesticides should be applied to the foliage thoroughly, allowing excess to run off into the soil beneath the plant. Repeat at least twice at two week intervals. Pesticides appropriate for ornamentals may not be safe for vegetable and fruit crops. Read and follow the label instructions on all pesticides.
3. Use sticky substances. Adult weevils emerge from soil and debris at night and climb the plants to eat. Lower trunks of host plants may be wrapped with a four inch band of masking tape and the product Tanglewood applied to the taped surface. Check for buildup of dead insects regularly, and refresh as needed.
4. Try an organic solution. Weevils are attracted to water and may be trapped in shallow pans inset into the soil near affected host plants. Products that contain the organically derived insecticide spinosad are also labeled for leaf-feeding beetles on a wide variety of plants, and may be worth a try. Diatomaceous earth dusted at the base of affected plants is useful. In serious infestations, the lower sides of stems and leaf undersides should also be dusted.
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文章
Dummer. ゛☀
2017年09月18日
Hens and Chicks plant (Sempervivum spp.) produce rosettes of thick leaves that cluster together in colonies of both large and small plants. Foliage color varies depending on the variety, but many feature green interior leaves surrounded by a ring of red or darker green foliage. Each Hens and Chicks rosette flowers approximately every four years, near the end of its life, but the plants are constantly producing new rosettes from the roots to replace those that fade. Hens and Chicks grow outdoors in U.S. Department of Agriculture hardiness zones 3 to 8, but you can grow them as houseplants everywhere.
1. Place potted plants in an area that receives full sunlight. Grow potted plants in a fast-draining succulent mix in a pot that contains at least one bottom drainage hole. Outdoors, plant Hens and Chicks in a sandy or rocky bed that drains quickly and receives full sun to part shade.
2. Water the plants only when the soil dries out completely. Water until moisture drips from the bottom of the pot and empty the pot’s drip tray after the soil finishes draining, usually within 30 to 60 minutes. Garden plants rarely require watering.
3. Cut old rosettes of foliage from the plant after they produce a flower and die back naturally. Cut the rosettes off the plant at ground level with a clean, sharp knife.
4. Remove offsets, or small new plants, from the outside of a group of Hens and Chicks to propagate new plants. Cut the small offsets from the small plants just below the soil surface with a sharp knife. Plant the rosettes in a well-draining bed or pot of succulent potting soil immediately after removal. The offsets quickly set roots and grow into new plants.
1. Place potted plants in an area that receives full sunlight. Grow potted plants in a fast-draining succulent mix in a pot that contains at least one bottom drainage hole. Outdoors, plant Hens and Chicks in a sandy or rocky bed that drains quickly and receives full sun to part shade.
2. Water the plants only when the soil dries out completely. Water until moisture drips from the bottom of the pot and empty the pot’s drip tray after the soil finishes draining, usually within 30 to 60 minutes. Garden plants rarely require watering.
3. Cut old rosettes of foliage from the plant after they produce a flower and die back naturally. Cut the rosettes off the plant at ground level with a clean, sharp knife.
4. Remove offsets, or small new plants, from the outside of a group of Hens and Chicks to propagate new plants. Cut the small offsets from the small plants just below the soil surface with a sharp knife. Plant the rosettes in a well-draining bed or pot of succulent potting soil immediately after removal. The offsets quickly set roots and grow into new plants.
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lrgarden：so beautiful
文章
Dummer. ゛☀
2017年09月18日
Every year about this time, stores of all sorts sell something called “Christmas Cactus”, a showy plant with segmented foliage that arches out over the sides of the pot. Since most people find the foliage relatively unimpressive, the seasonal specials are always sold in bud or with newly-opened blooms. The long, tubular flowers, which appear at the ends of the stems, are made up of many slender, pointed petals fused at the bases. Flower colors range from white through shades of peach, orange, purple, rose and red, with bi-colored varieties widely available.
Sometimes merchants trying for early sales offer the similar-looking “Thanksgiving Cactus” starting just after Halloween. To the casual buyer, these are dead ringers for Christmas Cactus and also bear a close resemblance to the “Easter Cactus” sold in the spring. To make matters just a little more complicated, the various holiday cacti are all sometimes sold under the exotic-sounding name “Zygocactus”.
So what is up with all of these holiday cacti? Is it all marketing or are they different plants? More to the point, if you are seduced by those showy blossoms, will your Thanksgiving/Christmas/Easter cactus survive for more than a few weeks? Southerners, especially older ones, will sometimes tell tales of family Christmas Cacti that have survived for generations. Are they talking about the same plants that now grace thousands of big box stores?
Even reference sources differ on the specifics of holiday cactus nomenclature. The experts at Clemson University identify Thanksgiving Cactus as a single species, Schlumbergera truncata, Christmas Cactus as Schlumbergera bridgesii and the closely related Easter Cactus as Hatiora gaertneri. English botanist Martyn Rix identifies Christmas Cactus as a hybrid, Schlumbergera x buckleyi, originally created in the 1840’s by a man named Buckley who crossed Schlumbergera truncata with Schlumbergera russelliana to create the progenitors of the modern hybrid Christmas cactus.
What does all this mean? For the average person—absolutely nothing. Those who have nurtured ancestral Christmas Cacti for decades can rest assured that their holiday plants are essentially the same as the specimens that today’s urban sophisticates buy in funky shops to decorate their minimalist apartments. All holiday cacti are very similar, except for bloom times. They are native to areas of Brazil near Rio de Janeiro, where they live as epiphytes, non-parasitic plants that flourish in trees, deriving sustenance from air, water and debris that collect around them. This is good news for those of us who love them, as they don’t need the bright sunlight required by terrestrial cacti. They also do not have the sharp spines of some of their relatives in the true cactus or Cactaceae family.
The vast majority of holiday cacti are sold growing in soil-like potting mix. What they really need is excellent drainage, not to mention caretakers who refrain from flooding them with water every day. Overwatering—which means watering before the soil is dry to the touch—can result in potentially fatal rot. If your holiday cactus is not thriving, cut back on water and repot it in a mixture of about 40 percent perlite—available at garden centers—and 60 percent fresh potting mix. Those who hate repotting plants can take comfort in the knowledge that holiday cacti bloom best when they are slightly pot-bound and only need repotting every three or four years.
All holiday cacti should come in before nighttime temperatures begin falling below 50 degrees Fahrenheit (10 degrees Celsius). Sometimes, if the plant undergoes dramatic temperature changes, flower buds will drop off. There is not much to be done, other than avoiding extremes the next time. Fertilize with a balanced, water-soluble houseplant fertilizer diluted to half strength. Stop fertilizing in late summer to encourage flower formation in Christmas and Thanksgiving cacti. Resume about a month after the flowers have bloomed.
Sometimes merchants trying for early sales offer the similar-looking “Thanksgiving Cactus” starting just after Halloween. To the casual buyer, these are dead ringers for Christmas Cactus and also bear a close resemblance to the “Easter Cactus” sold in the spring. To make matters just a little more complicated, the various holiday cacti are all sometimes sold under the exotic-sounding name “Zygocactus”.
So what is up with all of these holiday cacti? Is it all marketing or are they different plants? More to the point, if you are seduced by those showy blossoms, will your Thanksgiving/Christmas/Easter cactus survive for more than a few weeks? Southerners, especially older ones, will sometimes tell tales of family Christmas Cacti that have survived for generations. Are they talking about the same plants that now grace thousands of big box stores?
Even reference sources differ on the specifics of holiday cactus nomenclature. The experts at Clemson University identify Thanksgiving Cactus as a single species, Schlumbergera truncata, Christmas Cactus as Schlumbergera bridgesii and the closely related Easter Cactus as Hatiora gaertneri. English botanist Martyn Rix identifies Christmas Cactus as a hybrid, Schlumbergera x buckleyi, originally created in the 1840’s by a man named Buckley who crossed Schlumbergera truncata with Schlumbergera russelliana to create the progenitors of the modern hybrid Christmas cactus.
What does all this mean? For the average person—absolutely nothing. Those who have nurtured ancestral Christmas Cacti for decades can rest assured that their holiday plants are essentially the same as the specimens that today’s urban sophisticates buy in funky shops to decorate their minimalist apartments. All holiday cacti are very similar, except for bloom times. They are native to areas of Brazil near Rio de Janeiro, where they live as epiphytes, non-parasitic plants that flourish in trees, deriving sustenance from air, water and debris that collect around them. This is good news for those of us who love them, as they don’t need the bright sunlight required by terrestrial cacti. They also do not have the sharp spines of some of their relatives in the true cactus or Cactaceae family.
The vast majority of holiday cacti are sold growing in soil-like potting mix. What they really need is excellent drainage, not to mention caretakers who refrain from flooding them with water every day. Overwatering—which means watering before the soil is dry to the touch—can result in potentially fatal rot. If your holiday cactus is not thriving, cut back on water and repot it in a mixture of about 40 percent perlite—available at garden centers—and 60 percent fresh potting mix. Those who hate repotting plants can take comfort in the knowledge that holiday cacti bloom best when they are slightly pot-bound and only need repotting every three or four years.
All holiday cacti should come in before nighttime temperatures begin falling below 50 degrees Fahrenheit (10 degrees Celsius). Sometimes, if the plant undergoes dramatic temperature changes, flower buds will drop off. There is not much to be done, other than avoiding extremes the next time. Fertilize with a balanced, water-soluble houseplant fertilizer diluted to half strength. Stop fertilizing in late summer to encourage flower formation in Christmas and Thanksgiving cacti. Resume about a month after the flowers have bloomed.
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文章
Dummer. ゛☀
2017年09月18日
Cacti are flowering plants, so every kind of cactus is capable of blooming when it is mature. Whether or not an individual cactus plant blooms depends on its age and the care it gets. Some cacti don’t bloom until they are more than 30 years old. Others won’t bloom, even if they are old enough, unless they get proper light conditions, watering and fertilization. This is especially true for potted cacti. Holiday Cacti grown indoors, such as Christmas Cactus, won’t bloom unless they get long nights and short days.
Columnar Cacti
Tall-growing columnar cacti often take years before they bloom for the first time if grown from seed. If you root a branch from a mature, already-blooming columnar cactus, it will keep blooming after it is separated from the mother plant and rooted. However, some cacti, such as Saguaro (Carnegiea gigantea), native to Arizona in U.S. Department of Agriculture plant hardiness zones 9 through 11, have branches that won’t root, so Saguaro has to be grown from seed, with a 40- to 55-year wait for the first flower. Some columnar cacti that produce flowers for the first time after 10 to 20 years and can live outdoors in USDA zones 9 through 11 are Peruvian Apple (Cereus repandus) with blue stems and large white night-blooming flowers, Senita Cactus (Pachycereus schottii) with gray-green stems and small pink flowers produced amid an area of dense shaggy spines, and Mexican Fence Post (Pachycereus marginatus) with bright green stems that have white-defined stem ridges and smaller white flowers. Columnar cacti are effective landscaping plants even without flowers.
Short-stem Cacti
Short-columnar cacti with mature stems below 2 feet (60 cm) tall usually flower within five years from germination. Hedgehog Cacti (Echinocereus spp.) are native to the United States and Mexico, and make mounding clumps of many stems over time. Large pink, magenta or red flowers are abundant in spring. Depending on the species, Hedgehog Cactus grows in USDA zones 5, for red-flowered short claret cup (Echinocereus coccineus), through 11. Easter Lily Cactus (Echinopsis oxygona and hybrids) are hardy in USDA zones 8 through 11. They produce huge funnel-shaped flowers in white, pink, lavender, magenta or red. For the size of the plant, Peanut Cactus (Echinopsis chamaecereus) produces large flowers. Stems up to 6 inches (15 cm) long, covered with weak white spines, crawl along the ground and produce abundant bright orange flowers over 1 inch (2.5 cm) wide in spring. Peanut Cactus grows outdoors in USDA zones 8 through 11.
Round Cacti
Some of the most floriferous cacti belong here, such as Pincushion Cacti (Mammillaria spp. and hybrids) and Rebutias (Rebutia spp. and hybrids). They usually bloom within three to four years after sprouting. Pincushion Cacti are native to the United States and Mexico, producing star-shaped flowers in a ring around the top of the stem. Although round when young, some elongate to small columns. Flowers are white, pink, magenta, lavender, red, yellow or green, and plants grow outdoors in USDA zones 8 through 10. Rebutias are native to South America. Tidy low-growing plants cluster with age, and red, yellow, orange or purple flowers come from near the base of the stem. Rebutias are hardy in USDA zones 9 through 11.
Conditions that Encourage Bloom
Since cacti grow as container plants in any USDA zone, give them proper care and they will reward you with blossoms. Most cacti need at least four hours of sunlight a day, preferably morning sunlight. Water them regularly during the growing season, allowing the top inch or two of soil to dry before watering again until water comes through the pot’s drainage holes. Don’t let water remain in pot saucers. Use well-draining soilless potting mix. Fertilize them monthly from when they begin spring growth to the end of summer with a half-strength low-nitrogen high-phosphorus formula, which promotes bloom. Allow the cactus to become somewhat pot-bound for best bloom. Decrease watering in winter, and give your cacti a winter dormancy period with lower temperatures (50°F/10°C).
Holiday Cacti
Thanksgiving Cactus (Schlumbergera truncata) and Christmas Cactus (Schlumbergera bridgesii) look so different than desert cacti that some people are surprised that they are cacti. They look different because they grow on Brazilian rain forest trees as epiphytes, and their stems are flattened and green, looking leaf-like. They need different care than desert cacti. Holiday Cacti are triggered to bloom in fall and winter by cooling temperatures, increasing night length and decreasing day length with only 8 to 10 hours of light. Most of the year they prefer partial shade, but in fall and winter they can be in sunlight.
Columnar Cacti
Tall-growing columnar cacti often take years before they bloom for the first time if grown from seed. If you root a branch from a mature, already-blooming columnar cactus, it will keep blooming after it is separated from the mother plant and rooted. However, some cacti, such as Saguaro (Carnegiea gigantea), native to Arizona in U.S. Department of Agriculture plant hardiness zones 9 through 11, have branches that won’t root, so Saguaro has to be grown from seed, with a 40- to 55-year wait for the first flower. Some columnar cacti that produce flowers for the first time after 10 to 20 years and can live outdoors in USDA zones 9 through 11 are Peruvian Apple (Cereus repandus) with blue stems and large white night-blooming flowers, Senita Cactus (Pachycereus schottii) with gray-green stems and small pink flowers produced amid an area of dense shaggy spines, and Mexican Fence Post (Pachycereus marginatus) with bright green stems that have white-defined stem ridges and smaller white flowers. Columnar cacti are effective landscaping plants even without flowers.
Short-stem Cacti
Short-columnar cacti with mature stems below 2 feet (60 cm) tall usually flower within five years from germination. Hedgehog Cacti (Echinocereus spp.) are native to the United States and Mexico, and make mounding clumps of many stems over time. Large pink, magenta or red flowers are abundant in spring. Depending on the species, Hedgehog Cactus grows in USDA zones 5, for red-flowered short claret cup (Echinocereus coccineus), through 11. Easter Lily Cactus (Echinopsis oxygona and hybrids) are hardy in USDA zones 8 through 11. They produce huge funnel-shaped flowers in white, pink, lavender, magenta or red. For the size of the plant, Peanut Cactus (Echinopsis chamaecereus) produces large flowers. Stems up to 6 inches (15 cm) long, covered with weak white spines, crawl along the ground and produce abundant bright orange flowers over 1 inch (2.5 cm) wide in spring. Peanut Cactus grows outdoors in USDA zones 8 through 11.
Round Cacti
Some of the most floriferous cacti belong here, such as Pincushion Cacti (Mammillaria spp. and hybrids) and Rebutias (Rebutia spp. and hybrids). They usually bloom within three to four years after sprouting. Pincushion Cacti are native to the United States and Mexico, producing star-shaped flowers in a ring around the top of the stem. Although round when young, some elongate to small columns. Flowers are white, pink, magenta, lavender, red, yellow or green, and plants grow outdoors in USDA zones 8 through 10. Rebutias are native to South America. Tidy low-growing plants cluster with age, and red, yellow, orange or purple flowers come from near the base of the stem. Rebutias are hardy in USDA zones 9 through 11.
Conditions that Encourage Bloom
Since cacti grow as container plants in any USDA zone, give them proper care and they will reward you with blossoms. Most cacti need at least four hours of sunlight a day, preferably morning sunlight. Water them regularly during the growing season, allowing the top inch or two of soil to dry before watering again until water comes through the pot’s drainage holes. Don’t let water remain in pot saucers. Use well-draining soilless potting mix. Fertilize them monthly from when they begin spring growth to the end of summer with a half-strength low-nitrogen high-phosphorus formula, which promotes bloom. Allow the cactus to become somewhat pot-bound for best bloom. Decrease watering in winter, and give your cacti a winter dormancy period with lower temperatures (50°F/10°C).
Holiday Cacti
Thanksgiving Cactus (Schlumbergera truncata) and Christmas Cactus (Schlumbergera bridgesii) look so different than desert cacti that some people are surprised that they are cacti. They look different because they grow on Brazilian rain forest trees as epiphytes, and their stems are flattened and green, looking leaf-like. They need different care than desert cacti. Holiday Cacti are triggered to bloom in fall and winter by cooling temperatures, increasing night length and decreasing day length with only 8 to 10 hours of light. Most of the year they prefer partial shade, but in fall and winter they can be in sunlight.
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文章
Dummer. ゛☀
2017年09月18日
Calandrinia is a plant genus that contains many species of purslane, including the redmaids. The genus was named for Jean Louis Calandrini, an 18th-century Swiss botanist. It includes around 150 species of annual herbs which bear colorful flowers in shades of red to purple and white. Plants of this genus are native to Australia, Chile, and western North America.
Calandrinia are half hardy perennials and annuals. As the perennials have a short life span they are usually grown as half hardy annuals in the garden. They are low growing, reaching heights of about 6 to 18 inches (15 to 45 cm) and bloom with hundreds of bright pink and purple flowers from middle to late summer. Names for Calandrinia include Rock Purslane, Parakeelya and Redmaids. They are ideal, ground cover and edging plants, they can also be used in rockeries. Plants are able to grow in very hot conditions.
Growing Conditions and General Care
Calandrinia plants are very easy to care for as they can tolerate prolonged dry periods. They do not like to much water, especially in the winter. Plants are able to grow as a short lived perennial in warm regions but should be grown as annuals elsewhere. Propagate by taking cuttings or allow plants to self seed in situ.
If you plan to grow outdoors from seed then Calandrinia species should be sown at a depth of 0.1 inch (3 mm) after the last frost of spring. If you prefer to start off Calandrinia as seeds indoors then they should be started off about eight weeks before they are due to be put out.
They should be grown at a temperature of 55 to 59°F (13 to 15°C), and take from one to two weeks to germinate. The seedlings of Calandrinia should be planted out with a spacing of about 8 inches (20 cm) following the last possible frost of spring into an area that receives plenty of sun, and into a gritty or sandy soil.
Calandrinia are half hardy perennials and annuals. As the perennials have a short life span they are usually grown as half hardy annuals in the garden. They are low growing, reaching heights of about 6 to 18 inches (15 to 45 cm) and bloom with hundreds of bright pink and purple flowers from middle to late summer. Names for Calandrinia include Rock Purslane, Parakeelya and Redmaids. They are ideal, ground cover and edging plants, they can also be used in rockeries. Plants are able to grow in very hot conditions.
Growing Conditions and General Care
Calandrinia plants are very easy to care for as they can tolerate prolonged dry periods. They do not like to much water, especially in the winter. Plants are able to grow as a short lived perennial in warm regions but should be grown as annuals elsewhere. Propagate by taking cuttings or allow plants to self seed in situ.
If you plan to grow outdoors from seed then Calandrinia species should be sown at a depth of 0.1 inch (3 mm) after the last frost of spring. If you prefer to start off Calandrinia as seeds indoors then they should be started off about eight weeks before they are due to be put out.
They should be grown at a temperature of 55 to 59°F (13 to 15°C), and take from one to two weeks to germinate. The seedlings of Calandrinia should be planted out with a spacing of about 8 inches (20 cm) following the last possible frost of spring into an area that receives plenty of sun, and into a gritty or sandy soil.
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文章
Dummer. ゛☀
2017年09月18日
Zamioculcas zamiifolia also known as ZZ Plant thrives well in USDA Plant Hardiness Zone 9b through 11, and won’t tolerate so much as a hint of frost. The ZZ Plant is an ancient one whose prehistoric appearance may remind you of a cycad, though they aren’t related. Tough, drought resistant and low-light tolerant, this undemanding beauty may be the perfect plant for the forgetful or neglectful gardener. Gardeners who don’t water often are the ones this plant loves best.
1. Remove the ZZ Plant with yellowing leaves from its pot to rescue it. The discoloration is typically caused from too much water, which causes the water and food storing rhizomes to rot from fungal development. This so-called “eternal plant” will die from overwatering.
2. Shake as much soil from the root ball as you can. Discard it, don’t reuse it or add it to the compost heap as it’s probably infected with fungus. Set the plant on several layers of newspaper and examine the roots. You will probably find some soft, mushy roots and possibly rotting tubers as well. Using sharp, clean pruning shears, clip any diseased tissue that you see and discard it.
3. Pick any yellowing leaves off the ZZ Plant. If the stem is yellow, clip it off where it grows from the tuber. Check the tuber closely for signs of rot. Prune it out if it appears diseased.
4. Drench the roots and tubers with a fungicidal solution such as thiophanate-methyl. Follow the packaging instructions carefully.
5. Scrub the pot with hot, soapy water. Soak it in a solution of 9 parts water and 1 part bleach for 30 minutes. Rinse it thoroughly.
6. Combine equal parts cactus potting mix and perlite for an excellent ZZ Plant growing medium. Repot the plant, move it to a warm room with low lighting and withhold water for about a week to allow it to recover. ZZ Plants bounce back quickly from adversity and new shoots will soon emerge.
7. Return the ZZ Plant to its normal spot after a week of rest. This plant will do best with as much bright, indirect light as you can provide. While it will do well even in low light, more is better. Keep the temperature between 76 and 90 degrees Fahrenheit (24 and 32 degrees Celsius), with a range of between 80 and 87 degrees Fahrenheit (27 and 30 degrees Celsius) being optimum. Temperatures below 76 degrees Fahrenheit (24 degrees Celsius) will inhibit the plant’s growth.
8. Water your ZZ Plant thoroughly to evenly moisten the soil surface throughout the growing season. Allow the plant to dry out slightly between waterings. Water again when the top 1 inch (2.5 cm) of soil feels dry. Water no more than once weekly during the winter. Do not allow it to stand in water.
9. Feed this plant a balanced water-soluble houseplant fertilizer at half strength every two months while it is actively growing.
10. Set the ZZ Plant outdoors in a shady spot in the summer. It will appreciate the bright natural light and fresh air.
1. Remove the ZZ Plant with yellowing leaves from its pot to rescue it. The discoloration is typically caused from too much water, which causes the water and food storing rhizomes to rot from fungal development. This so-called “eternal plant” will die from overwatering.
2. Shake as much soil from the root ball as you can. Discard it, don’t reuse it or add it to the compost heap as it’s probably infected with fungus. Set the plant on several layers of newspaper and examine the roots. You will probably find some soft, mushy roots and possibly rotting tubers as well. Using sharp, clean pruning shears, clip any diseased tissue that you see and discard it.
3. Pick any yellowing leaves off the ZZ Plant. If the stem is yellow, clip it off where it grows from the tuber. Check the tuber closely for signs of rot. Prune it out if it appears diseased.
4. Drench the roots and tubers with a fungicidal solution such as thiophanate-methyl. Follow the packaging instructions carefully.
5. Scrub the pot with hot, soapy water. Soak it in a solution of 9 parts water and 1 part bleach for 30 minutes. Rinse it thoroughly.
6. Combine equal parts cactus potting mix and perlite for an excellent ZZ Plant growing medium. Repot the plant, move it to a warm room with low lighting and withhold water for about a week to allow it to recover. ZZ Plants bounce back quickly from adversity and new shoots will soon emerge.
7. Return the ZZ Plant to its normal spot after a week of rest. This plant will do best with as much bright, indirect light as you can provide. While it will do well even in low light, more is better. Keep the temperature between 76 and 90 degrees Fahrenheit (24 and 32 degrees Celsius), with a range of between 80 and 87 degrees Fahrenheit (27 and 30 degrees Celsius) being optimum. Temperatures below 76 degrees Fahrenheit (24 degrees Celsius) will inhibit the plant’s growth.
8. Water your ZZ Plant thoroughly to evenly moisten the soil surface throughout the growing season. Allow the plant to dry out slightly between waterings. Water again when the top 1 inch (2.5 cm) of soil feels dry. Water no more than once weekly during the winter. Do not allow it to stand in water.
9. Feed this plant a balanced water-soluble houseplant fertilizer at half strength every two months while it is actively growing.
10. Set the ZZ Plant outdoors in a shady spot in the summer. It will appreciate the bright natural light and fresh air.
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文章
Dummer. ゛☀
2017年09月18日
Succulents are a popular gardening trend that won’t be dying anytime soon. Enthusiasts love their geometric forms and exquisite, often intricate patterns and details. No longer viewed as just a desert or house plant, succulents can grow and actually thrive in various climates, depending on the type of succulent. In regions affected by drought, they are a smart, drought-tolerant alternative to thirsty lawns and other water-guzzling plants.
With very little effort, succulents can look so good. But they still require attention. Discover how to not only keep them alive, but get them to thrive.
1. Don’t Overwater Them
You love your succulents so much, you want to water them every other day to make them grow plump and lush. But what you’ll get is a soft, shriveled, squishy mess. Overwatering is a bigger problem for succulents than underwatering. Roots can rot. If it’s too late, look for healthy tissue, take some cuttings, and allow the cut end to callus (seal itself) and then replant it. Get rid of the soil in which the oversaturated succulent was in.
2. Don’t Neglect Them
Succulents and cacti: those are the desert-like plants that don’t need to be watered, like, ever—right? Wrong. Their watering needs are minimal, but they still need it to survive. If you live in a region that doesn’t get much rain, water succulents regularly during their periods of active growth. This would be spring through fall.
Container plants can be watered about once a week. Occasionally, let the hose drench the pot until water flows out, to remove built-up salts from the soil.
3. Group Plants with Similar Water Needs
In other words, don’t plant succulents next to super-fussy perennials that require rich soil and frequent watering. Ideally, you want to have a drought-tolerant, low-water area in your garden, a moderate water area, and so on. It just makes things easier for you and your plants will be happier.
4. The Right Soil
Cactus and succulent-mix soil is available by the bag at nurseries and home centers. While it’s useful for container plants, especially those that will be used as houseplants, it’s not always practical or necessary for succulents planted in the garden. Learn more about the type of soil that’s in your yard, and add amendments to make it fast-draining and on the dryer side.
While some succulents are so forgiving and will grow almost anywhere, even in clay, it’s best to give them optimal growing conditions for healthy roots and beautiful plants.
5. Shed Some Light
Most succulents need a mix of sunlight and shade to grow healthy. One extreme or the other is not going to result in a beautiful, happy plant. Learn about your particular succulent’s light requirements, and find the best place in your yard or space in which it plant it.
A hint: the color of the plant is a tip-off to its light needs. For example, shade-loving succulents are usually in hues of yellow and green. Sun lovers are more reddish and orange.
6. Protect from Frost
Succulents go dormant during the winter months, when they don’t need to be watered. In fact, watering them during dormant season can make their roots more susceptible to rot, and kill them. What they really like is a cool and dry climate.
If your area is experiencing lots of rain, and your succulents are in pots, move them under eaves to avoid over-saturation, or bring them inside.
Frost is another matter. Pay attention to freeze warnings. Cover with a cloth or plant under a tree, which protects succulents during the winter and summer.
7. Put Them in the Ground
Some people think that succulents are houseplants, and when they are grown outdoors, must be relegated to containers and pots. While they look great in a well-designed container arrangement, succulents, just like any other plant, love to be planted in garden beds where they can be fruitful and multiply. In warmer regions that don’t experience freezing temperatures during the winter, succulents will do just fine growing in the ground or raised beds.
Some are so forgiving of soil conditions that they can grow almost anywhere that has at least some soil to which they can attach their roots.
8. Allow to Callus Before Transplanting
Succulents are one of the easiest plants to propagate: just take a snippet, some leaves, a stem, offset, or “baby” and plop into the soil or another pot. But before you do, allow the stem to callus-over for a few days to prevent rot. This can be done by either placing cuttings or a paper towel and leaving them for up to five days, or putting them in a container or other place where you will remember to replant them.
9. Get Rid of Harmful Insects
One thing is certain: your succulent or cacti is not looking good. Symptoms include: buds that won’t open, distorted growth, cotton-like attachments to roots, tiny insects on new growth, paprika-like dots on leaves, brown bumps on stems, collapsed outer leaves, holes in leaves.
The culprit? Insects. Some gardeners believe that hardy succulents and cacti are resistant to insects–not so. Consult a master gardener site online or get one of the books about succulents and cacti to help you identify the symptom, insect, and solution.
10. Protect from Disease
One sign of disease in succulents is an orangeish, cancerous-like growth near or on the stem. It has probably become infected by a microscopic mite. To treat: remove the infected tissue and put the succulent in a separate container until new, healthy growth appears. To prevent spreading to other plants, remember to clean your tools after using them on infected succulents.
With very little effort, succulents can look so good. But they still require attention. Discover how to not only keep them alive, but get them to thrive.
1. Don’t Overwater Them
You love your succulents so much, you want to water them every other day to make them grow plump and lush. But what you’ll get is a soft, shriveled, squishy mess. Overwatering is a bigger problem for succulents than underwatering. Roots can rot. If it’s too late, look for healthy tissue, take some cuttings, and allow the cut end to callus (seal itself) and then replant it. Get rid of the soil in which the oversaturated succulent was in.
2. Don’t Neglect Them
Succulents and cacti: those are the desert-like plants that don’t need to be watered, like, ever—right? Wrong. Their watering needs are minimal, but they still need it to survive. If you live in a region that doesn’t get much rain, water succulents regularly during their periods of active growth. This would be spring through fall.
Container plants can be watered about once a week. Occasionally, let the hose drench the pot until water flows out, to remove built-up salts from the soil.
3. Group Plants with Similar Water Needs
In other words, don’t plant succulents next to super-fussy perennials that require rich soil and frequent watering. Ideally, you want to have a drought-tolerant, low-water area in your garden, a moderate water area, and so on. It just makes things easier for you and your plants will be happier.
4. The Right Soil
Cactus and succulent-mix soil is available by the bag at nurseries and home centers. While it’s useful for container plants, especially those that will be used as houseplants, it’s not always practical or necessary for succulents planted in the garden. Learn more about the type of soil that’s in your yard, and add amendments to make it fast-draining and on the dryer side.
While some succulents are so forgiving and will grow almost anywhere, even in clay, it’s best to give them optimal growing conditions for healthy roots and beautiful plants.
5. Shed Some Light
Most succulents need a mix of sunlight and shade to grow healthy. One extreme or the other is not going to result in a beautiful, happy plant. Learn about your particular succulent’s light requirements, and find the best place in your yard or space in which it plant it.
A hint: the color of the plant is a tip-off to its light needs. For example, shade-loving succulents are usually in hues of yellow and green. Sun lovers are more reddish and orange.
6. Protect from Frost
Succulents go dormant during the winter months, when they don’t need to be watered. In fact, watering them during dormant season can make their roots more susceptible to rot, and kill them. What they really like is a cool and dry climate.
If your area is experiencing lots of rain, and your succulents are in pots, move them under eaves to avoid over-saturation, or bring them inside.
Frost is another matter. Pay attention to freeze warnings. Cover with a cloth or plant under a tree, which protects succulents during the winter and summer.
7. Put Them in the Ground
Some people think that succulents are houseplants, and when they are grown outdoors, must be relegated to containers and pots. While they look great in a well-designed container arrangement, succulents, just like any other plant, love to be planted in garden beds where they can be fruitful and multiply. In warmer regions that don’t experience freezing temperatures during the winter, succulents will do just fine growing in the ground or raised beds.
Some are so forgiving of soil conditions that they can grow almost anywhere that has at least some soil to which they can attach their roots.
8. Allow to Callus Before Transplanting
Succulents are one of the easiest plants to propagate: just take a snippet, some leaves, a stem, offset, or “baby” and plop into the soil or another pot. But before you do, allow the stem to callus-over for a few days to prevent rot. This can be done by either placing cuttings or a paper towel and leaving them for up to five days, or putting them in a container or other place where you will remember to replant them.
9. Get Rid of Harmful Insects
One thing is certain: your succulent or cacti is not looking good. Symptoms include: buds that won’t open, distorted growth, cotton-like attachments to roots, tiny insects on new growth, paprika-like dots on leaves, brown bumps on stems, collapsed outer leaves, holes in leaves.
The culprit? Insects. Some gardeners believe that hardy succulents and cacti are resistant to insects–not so. Consult a master gardener site online or get one of the books about succulents and cacti to help you identify the symptom, insect, and solution.
10. Protect from Disease
One sign of disease in succulents is an orangeish, cancerous-like growth near or on the stem. It has probably become infected by a microscopic mite. To treat: remove the infected tissue and put the succulent in a separate container until new, healthy growth appears. To prevent spreading to other plants, remember to clean your tools after using them on infected succulents.
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