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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
Tree care is a critical investment for the future of your landscape. So while brown leaves, dead limbs, and the like don't always mean you have a dying tree, it's important to take notice of such troubling signs and learn their causes. The following are some of the dividends you'll earn on your investment in caring for your yard's gentle giants, assuming you handle it correctly: Increasing property values Beautifying your surroundings Purifying your air Saving energy by providing cooling shade from summer's heat and protection from winter's wind I receive many questions about tree care from readers, a sampling of which I've provided below.[图片]Why Are the Leaves on My Japanese Maples Turning Brown? There's a reason that Japanese maple trees are among the most popular specimens in the landscape. Their leaves look wonderful throughout the growing season, not just in autumn. For fall foliage colors, they offer gold as well as red. So-called "dissected" types exhibit interesting leaf shapes, to boot. But with Japanese maples, it is not uncommon to see the leaves turning brown in summer. Click the tree care link above to learn why this problem occurs.[图片]Why Do I Have Brown Leaves on My Magnolia Trees? Unlike Japanese maples, magnolia trees have something besides foliage to brag about. Magnolia trees are one of the most popular specimens in the spring landscape, due to their beautiful blossoms. But the appearance of brown leaves out of season is a troubling sight on any specimen. Consult the FAQ linked to above to learn why context is everything when it comes to asking why your magnolia trees have brown leaves.[图片]My Magnolia Trees Have Not Only Brown Leaves But Dead Branches. How Much Should I Prune? If brown leaves scare homeowners, then dead branches should send them into shock! But wait; all is not lost, necessarily. When you detect dead branches, the tree care task awaiting you involves both action and scrutiny. Above all, remain calm, and consult the FAQ linked to above.[图片]My Young Bradford Pear Tree Now Has Brown Leaves That Are Wilted. What's Up? Bradford pear trees flower profusely in spring and afford excellent autumn color. But the experts warn that it's a mistake to plant Bradford pear trees, and rightly so: their limbs break too easily in stormy weather. I've seen the limbs of too many Bradford pear trees lying on the ground after a good wind to buy one, myself. But if you've already planted a young Bradford pear tree, your hope is that, through proper tree care, you can derive as many years as possible from your specimen. Your tree care work may well begin with the challenge represented by the FAQ linked to above.[图片]My Magnolia Trees Developed Brown Leaves. The Foliage Also Got Black Spots on It. The Leaves Fell Off. What's the problem? Have black spots on your magnolia tree foliage? Find out what they are -- and what you can do about this problem. The Leaves on My Bradford Pear Tree Are Turning Brown. Should I Give It More Water? As the answer to this FAQ reveals, you can't automatically assume you need to water a tree more just because it has brown leaves when its foliage would normally be green. The Leaves on My Emerald Cedar Tree Started Turning Brown Last Summer. What's the Problem? This problem regards browning on a plant actually named 'Emerald Green' arborvitae, but some people use the nickname "Emerald cedar." Find out the possible reasons why this plant's foliage might turn brown in summer.[图片]Tree Problems Caused by Insects Insect pests can wreak havoc with trees. And what makes tree problems caused by insects especially difficult to cope with is that, sometimes, the pests we detect on a tree aren't the ones causing the problem. Below I present a sampling of Q&As dedicated to this topic: My Red Spruce Trees Are Being Attacked by Insects (Beetles). How Do I Stop the Spread? Speaking of deadly attacks on trees from insect pests, certain beetles can spell major problems for your specimen trees. As I explain in the FAQ linked to above, proper tree care, in this case, demands good timing and a belief that neatness counts. Scale Insects Have Infested My Magnolia Tree. How Do I Control Magnolia Scale? Scale insects are among the oddest looking insects you'll ever see. Click the link to this FAQ to learn how to control magnolia scale.[图片]My Young Blue Spruce Tree Is Developing Bare Branches. Is It Dying? Insects may be the culprits here. Consult this FAQ to find out which insects would be the "usual suspects" -- and how to control them. What Pest Makes Those Little Holes in a Tree? Is It an Insect? As you'll see in the answer to this tree problem question, it all depends on the nature of those "little holes." In one scenario, you don't have to worry about the culprit; in another, the culprit is an insect pest about which you very much need to worry.[图片]How Do You Treat Ants and Sooty Mold on a Magnolia Tree? If your tree is struggling and has insects on it, you can't just assume that those particular insects are at the root of the problem. Here's a case where insects (ants) and sooty mold are effects, rather than the cause of a problem. Yellow Leaves on Trees - What's the Reason? Your tree has yellow leaves. Does that yellowing signify a tree problem? Well, it depends on the circumstances. Obviously, if you grow fall foliage trees and they are displaying that color in fall, there's a good chance that the foliage is supposed to look that way. But what about other times of the year? Or what about other types of trees? Well, it still depends on the circumstances, as you'll discover by clicking the first two links below dealing with the issue of yellow leaves on trees.[图片]My Southern Magnolia Has Yellow Leaves. Is It Dying? We begin with a case of yellow leaves on a southern magnolia. Why Did the Flowers on My Bradford Pear Turn Black?In this FAQ, the operative color is black, not yellow. Fire blight disease is so called because it causes tree parts to turn black. Find out how to treat fire blight by reading this tree problem FAQ. Does It Help to Fertilize an Injured Tree? Fertilizing has its place in tree care, but does it play a role in nursing an injured tree back to health? My Magnolia Tree is Getting Too Big and I'd Like to Make It More Compact. What Is the Best Time for Pruning Magnolia Trees? In this FAQ, I answer the question of when to prune magnolia trees -- but with a caveat.[图片]How Do You Care for a Potted Magnolia Tree? It's easy enough to fulfill sunlight requirements for a potted magnolia tree, but proper watering isn't so easy to achieve. Why Isn't My Flowering Tree Blooming? A "flowering tree" not flowering: Is that a contradiction in terms? Well, Mother Nature apparently doesn't see it that way. Find out some of the possible reasons why a flowering tree might fail to bloom. How Do You Straighten a Leaning Tree? If your tree leans and you've tried -- but failed -- to straighten it out, you'll want to consult the answer to this tree problem FAQ.[图片]Why Are My Dwarf Alberta Spruce Trees Experiencing Needle Drop? Needle drop on evergreens can be scary, but it's not necessarily fatal. Learn what may be causing needle drop on your evergreen tree -- and what to do about it. Can You Spread Soil Over Exposed Tree Roots and Grow Plants on Top of Them? ​This isn't the best of ideas, and I explain why it's not in this FAQ, offering an alternative. Winter Damage to Trees In the following entry, I discuss another problem: a case of coping with the challenges posed by warm climates. In the last two FAQs, I point to examples where tree "damage" might be your first thought upon observing strange growths (bumps) on trees, but they turn out to be nothing harmful.[图片]Do You Have Any Tips for Protecting Japanese Maple Trees From Snow and Ice Damage? In addition to some of the more direct steps you can take to protect Japanese maple trees (and others) from winter damage, this FAQ looks at some less obvious steps that you could easily overlook. Our Bradford Pear Lost Limbs From Snow and Ice Damage. What Should We Do? Some tree problems are the result of poor plant selection. Bradford pear trees are notorious for losing branches due to wind, ice and snow damage. Why Don't the Buds on My Magnolia Tree Open Up? There are a number of possible answers to this question. I offer three potential reasons why magnolia buds fail to open in this FAQ. Two of those reasons are weather-related.[图片]Can You Grow Dwarf Alberta Spruces in Pots in Warm Climates? Dwarf Alberta spruces are best grown in zones 3 to 8, but this reader wishes to "break the rule" -- or try to, anyhow. I suggest a way to "cheat" that might make it possible to grow dwarf Alberta spruces in warm climates. What Are Those Odd-Looking Growths on My Magnolia Trees? Although our trees sometimes exhibit signs of having been damaged, some tree "damage" turns out, upon further inspection, to be a false alarm. We detect something (perhaps something we'd describe as an "odd growth") we've never noticed before, and it worries us -- until we've undergone the necessary learning process to find out what the heck it is! Such is the case in this FAQ, which you can access by clicking on the link above.[图片]The Leaves of My River Birch Tree Have Growths on Them. What Problem Does My Tree Have? Another case of "mysterious growths" or bumps -- but once again, nothing that indicates any serious damage. Why Should I Be Watering Evergreen Trees in Autumn? Hint: It's a matter of thinking ahead. When Should I Be Watering Trees in Fall? You know the "Why?", now learn the "When?" When Should You Fertilize Trees? In general, fertilize trees in spring. This will result in surprisingly vigorous new growth, including a thicker leaf canopy. The foliage will also display a richer color as the result of the application of tree fertilizers. By the way, yes, you should still apply tree fertilizers even to older specimens, even though it's natural to think that they're "big enough already." They need the nutrients to stay healthy.[图片]What Is the Proper Way of Pruning Trees? There are many different kinds of pruning cuts, but the following tips will give beginners the basics of what they need to know about the proper way of pruning trees, generally. If you must prune off a scaffold branch (see below), make sure, first of all, that the branch does not begin to fall prematurely, while still attached to the trunk. This would cause a rip at the joint where the branch meets the trunk, thus creating an open sore that invites disease. To avoid this scenario, make your cuts in the following manner to reduce pressure on this joint: At a point along the branch approximately 2-3 feet away from the trunk, begin by sawing about half way through the branch from the bottom. Now, from the top, but an inch or so further out from the branch than the first cut (more for thicker branches), saw through the rest of the branch, to remove it. You've now removed all but 2-3 feet of the branch. The remaining stub won't weigh enough to put undue pressure on the aforementioned joint.[图片]Now proceed to prune off the remaining stub, as indicated below. With the danger of ripping thus eliminated, we can prune off the remaining 2-inch to 3-inch stub. To do so, acquaint yourself with a tree part known as a branch "collar." A branch's "collar" is the swelled base of the branch where it meets the tree trunk. Think of it as an intermediate area between the branch and the trunk. To finish pruning off the branch, saw it off just outside the branch collar. Leaving the branch collar intact will promote healing. If you are merely shortening a scaffold branch on a young tree, prune the branch back to a lateral bud or other branch. What exactly is a "scaffold branch?" A scaffold branch is one of the primary limbs radiating from the trunk of a tree. All subordinate limbs stem from the scaffold branches. By establishing what the latter will be for a particular specimen early on, you can prune accordingly and shape it so as to achieve optimal form. This is one of the most important aspects of early tree care.[图片]What Is the Best Time to Prune Trees? You can cut dead or diseased branches off trees (whether evergreen or deciduous) at any time of the year, as soon as you see them. But what is the best time to prune trees, with the intention of thinning out healthy branches? The job is best done, generally speaking, in late winter. For example, pruning oak trees at this time will help avoid problems with oak wilt, to which the trees are more susceptible April-June. An exception can be made for plants with a high sap flow in late winter, such as maple trees. The best time to prune such trees is late spring or early summer. In thinning out trees, you'll be removing branches that are alive and disease-free, but ill-positioned or otherwise undesirable. For instance, you shouldn't have any two branches of your trees coming into contact with each other. Such contact invites disease and an overly thick canopy casts too much shade on the tree's lower branches.[图片]True, in the case of flowering trees (such as weeping cherry trees), specifically, pruning off such branches in late winter may lessen the impact of the specimen's floral display for that year. But in the long run, the pruning will be beneficial.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
Homeowners frequently wonder why their crepe myrtle shrubs develop brown leaves. The fact is, one simple reason cannot be given to account for this browning. That is because the nature of the issue depends on the time of year when the problem occurs. We also have to be careful to specify that we are talking here about the whole leaf turning brown (sometimes accompanied by curling), or about the foliage browning around the edges, as opposed to the emergence of brown spots in the middle of the leaf.[图片]Such spots can indicate Cercospora leaf spot, which is caused by a type of fungus (Cercospora lythracearum) -- and an entirely different problem. Give your bushes plenty of space (to promote good air circulation) when you plant them, and prune off (and properly dispose of) affected branches (to prevent transmission of the fungus) to ward off Cercospora leaf spot. Better yet, select cultivars resistant to this disease, a number of which you can find on the Alabama Cooperative Extension website.[图片]Brown Leaves on Crepe Myrtles: the Why Depends on the When But let's assume that the browning that you are seeing occurs on the entire leaf or around its edges (rather than in the form of spots). Consider two different scenarios: You witness the problem in summer You witness the problem in spring If you are seeing brown leaves (or even partially brown leaves) on crepe myrtle shrubs at the end of a dry summer, your crepe myrtle's browning foliage could be due to drought.[图片]These bushes flourish in the southeastern United States, where they are very popular due to their ability to withstand the summer heat. Nonetheless, they do need water, and they may dry up during especially hot summers during which there is little rainfall. Northerners who grow the bush (it is not nearly as popular in the North) are far less likely to experience a problem with their crepe myrtles drying out. This is more of an issue for Southern growers, who garden under more extreme conditions in summer. The result is browning of the foliage. The solution (in terms of preventative measures that you can take) to the problem is to provide the plant with artificial irrigation in sufficient quantity (keep the soil evenly moist, but not wet).[图片]If, by contrast, you are seeing brown leaves on the plant in spring, it could be due to your area having experienced a cold snap. Crepe myrtle is not as tolerant of cold weather as many bushes are. An untimely drop in temperature after the tender leaves have made their appearance can spell death for them. Short of growing your bush in a sheltered area (which requires foresight), there is not much that you can do to avoid the problem of browning in this case.[图片]Will My Crepe Myrtle Die? Here is the good news: neither case of brown leaves (that is, either in summer or in spring) need be fatal to your crepe myrtle. Browning due to a moderate cold snap ruins the appearance of the plant, but it probably will not kill your shrub. And while this bush is more likely to die from drought, it is usually easy enough to remedy the situation with artificial irrigation once you detect the first hint of browning.[图片]Obviously, in the latter case, vigilance is of the utmost importance. Keep tabs on your plants. Inspect them on a daily basis. Stay ahead of the game. If your crepe myrtle shrubs do not seem to be performing as they usually do, start asking questions. Many plant problems can be solved fairly easily if you learn about them soon enough and take appropriate action in a timely fashion. Do you tend to have trouble keeping up with your landscaping chores? Read my landscape maintenance checklist to stay organized.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
"Why do I have brown leaves on my magnolia trees?" Have you ever asked that question? You are hardly alone. These specimens can be magnificent, but they can also be plagued with problems. Brown leaves on magnolia trees could be the result of any one of a number of factors. Three such possible reasons are presented below, along with (where appropriate) a solution to the problem.[图片]Possible Reasons for the Dead Foliage, How to Prevent It A context must be provided to answer this tree-care question properly. We must first know: The type of magnolia tree in question. The time of year when the discoloration occurs. Some magnolia trees are deciduous, such as saucer magnolia trees (M. x soulangiana), and some are evergreen, such as Southern magnolia (M. grandiflora). If your own tree is a deciduous type, then you have nothing to worry about if the issue occurs during the fall season: its leaves are supposed to turn brown and fall in autumn.[图片]If, on the other hand, the brown leaves appear in spring, it could mean that there was frost damage. The good news is that such frost damage is unlikely to kill your tree. The bad news is that it will ruin the plant's appearance for a while, and that there is precious little you can do to prevent frost damage on a mature specimen. However, if you have just brought a small tree home from the garden center, you have the option of selecting a planting location for it that will be more likely to keep frosts off the foliage. An example of such a sheltered area would be one close your house. If the plant is still small enough, you may also be able to throw a sheet (or a similar covering) over it on a night when a frost is expected in your area (but remember to remove it next morning). For a mature magnolia tree, your options are more limited.[图片]However, you can try taking the following measures: Soak the soil around the root zone of the plant. The air temperature above damp ground tends to stay warmer than that above drier ground. Set up a patio heater (if you have one) near the plant (but not so close that it actually heats up the foliage). Always follow safety instructions to the letter when running such devices. Spray an antitranspirant on the tree's leaves to offer some protection.[图片]If the browning appears in summer, inadequate watering may be the cause of brown leaves, although high winds could also be the culprit (they dry out the foliage). The former is a more serious problem, but there is still no reason to be hasty in concluding that your magnolia tree has died. It is best to exercise patience, giving the plant time to recuperate. As preventive measures: Plant new trees in a sheltered area if your region is subject to high winds. Make sure the soil in the root zone is kept evenly moist.[图片]Finally, if the problem is happening in spring or summer, ask yourself this question: Do the brown leaves fall off almost immediately after the color change? That could signal a nutritional problem knows as "iron deficiency." I would recommend you have a soil test done (your county extension should be able to handle this).
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
A reader wrote in about newly planted Bradford pear trees, saying that they had borne the brunt of high winds for a couple of days. The Bradford pears on the property developed brown leaves; they suffered from leaf wilt and looked dead, despite the homeowner's keeping the ground damp. So what, if anything, can be done in cases like this? [图片]Windy Weather Only Partly Responsible for Leaf Wilt and Related Diseases Bradford pears and other trees that have just been transplanted experience transplant shock in a great many cases. Their roots have been disrupted, and they can be quick to show their displeasure. If someone picked you up, carried you out of your home and plopped you down on a strange property, you probably would be none too happy, either.[图片]In its state of shock, the damaged Bradford pear tree's roots can't send water up to the leaves as they normally would. Pounding winds make matters worse. One result can be leaf wilt. Other plant problems can be caused by these conditions, as well, on deciduous trees. The Purdue University Cooperative Extension Service lists some of them: Leaf scorch. Yellowing of the leaves. Leaf rolling. Curling of the leaves. Purdue observes that, at its onset, leaf scorch is indicated by the coloration of the "tissue between the veins or along the margins of leaves" becoming yellow, and that, as the problem progresses, this tissue becomes dry, resulting in a brown color.[图片]What Is the Treatment for Leaf Wilt on Bradford Pear Trees? What can you do to revive Bradford pear trees that have fallen prey to leaf wilt? Sadly, there is not much at this stage of the game that you can do. This is a case where prevention before the fact is more effective than treatment after the fact. For future reference, windbreaks could have minimized wilt damage, but it is rather late for that once the wilting has taken place. One should, however, emphasize what not to do: Do not fertilize. By feeding the plants, you would be encouraging additional leaf growth. That is not something that you want at this point. The root system can't support the canopy as it is, as said above; so there is no sense in adding to its burden.[图片]Provide the Bradford pear trees with irrigation regularly. Other than that, all you can do is exercise patience and see if they revive from their transplant shock and subsequent leaf wilt. Transplant Shock and "Bare-Root" Plants As the same Purdue source points out, "Bare root trees and shrubs are most susceptible to transplant shock. Such 'stressed' plants are very fragile and are more susceptible to other stress factors." If you are used to buying plants at garden centers growing in flats or pots (or balled-and-burlapped, in the case of trees), then that terminology, "bare-root" might leave you scratching your head. But the definition of this term is surprisingly straightforward: Bare-root plants are shipped with no soil "clothing" their roots. When you buy shrubs at the garden center, they may well come in containers, but when you order them from garden catalogs, they will often arrive as bare-root plants.[图片]You may wonder if shipping a plant with no soil on its roots is harmful to the plant. The fact is, not just any plant can be shipped bare-root. But certain plants -- for example, rose bushes -- can survive this method of transport in a sort of dormancy. But do not push your luck! Planting bare-root plants as soon as possible after they have arrived by mail is recommended. And if you cannot plant immediately, at least place the roots in water.[图片]As faithful as you might be in following these instructions, though, there is simply a lot that can go wrong when installing new plants -- whether it be bare-root or not. One of the "stress factors" cited by Purdue is drainage problems. To improve the chances that your new Bradford pear tree (or other plant) will survive and thrive, ensure that the soil under and around your plant's roots drains well, so that water won't collect and rot the roots.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
A reader wrote in about newly transplanted weigela shrubs suffering from leaf-wilt, noting that it had been very windy in his area of late. The weigela leaves wilted in spite of his keeping the ground damp. So are the plants dead? What, if anything, can be done for plants with wilted leaves?[图片]See my answer below: Why Do Leaves Wilt? It is important to realize that not all leaf-wilt is created equal. Rather, there are a number of different reasons why leaves wilt. Before taking any action, you must determine which of these reasons applies to your wilting plant: Damaged roots Lack of water Fungal infection Plant roots draw water out of the ground and send it up through the above-ground parts of the plant. If the roots are damaged, the flow of water to the leaves is reduced. Wilting leaves can result.[图片]Roots can sustain damage from a number of sources, including from: Transplant shock Physical injury from digging (while cultivating around the plant, etc.) Overwatering It is common when transplanting shrubs, including weigela shrubs, to cause transplant shock. The disturbed roots find it difficult to nourish the leaves with sufficient water in their damaged state, as the roots of a healthy, established shrub would. High winds simply exacerbate the problem: they have a drying effect that further robs the leaves of moisture. The result is leaf-wilt.[图片]Direct Answer to the Reader's Question Assuming that transplant shock is the reason behind the wilting leaves in your case, the positive actions you can take to help the weigela shrubs, at this point, are limited. Unfortunately, only forethought can prevent (or, at least, minimize) the effects of transplant shock. Windbreaks would have been effective (to shelter your weigela from drying winds). Likewise, you can prevent or minimize leaf-wilt by picking the best times to transplant. By avoiding transplanting at the hottest times of the year, you put less stress on the plants' root systems, thereby keeping them healthier.[图片]But the good news is that your weigela bushes are not dead: they just need time to recover. Here is what not to do: do not fertilize. Fertilizing would foster extra leaf growth -- which you do not want, since the weigela shrubs' disturbed roots are already struggling to support the current amount of foliage. Do water your weigela shrubs when the soil is dry, but do not overwater. When a plant's roots have been damaged (from transplant shock or any other source), they have to be given time to heal. Flooding a root system with water when that system is incapable of absorbing the water is, at best, useless and, at worst, counterproductive.[图片]Root damage can also be caused by digging too close to your plant while cultivating. For example, some gardeners will dig around a plant to remove weeds and accidentally sever roots in the process. You can largely avoid this problem by mulching. Others make the mistake of cutting into root systems when working compost or manure into the soil. Here the solution is to apply, instead, a compost tea or manure tea, which involves no digging. Again, once the damage has occurred, resist the temptation to combat the resulting leaf-wilt by overwatering (which will do no good). Finally, overwatering, itself can damage plant roots. The roots essentially rot and lose their ability to take up water. Adding more water in such a case can be like adding fuel to a fire.[图片]What if the Reason for Leaf-Wilt Is Not Root Damage? I have already mentioned a couple of alternate reasons for leaf-wilt, above. One is a soil fungus. Weigela shrubs are, in fact, one of the plants susceptible to the fungus, Verticillium wilt. According the University of Minnesota Extension (UVM), one way to identify this fungus is to look for "a scorched appearance" on leaf margins. To combat Verticillium wilt, UVM recommends selecting resistant plants and providing basic care (proper watering, fertilizing, etc.).[图片]That leaves one last cause of leaf-wilt, the one that most gardeners think of immediately: namely, lack of water. Yes, sometimes the reason is no more complicated than that the soil has dried out around your plant. If you do not see scorched leaf margins on your plant and have no reason to believe that root damage has occurred, you're lucky. Solving the problem is as easy as giving the plant a drink of water.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
Now that you have Basil Downy Mildew, what do you do next? It is a highly contagious disease, with little warning. Because it is transmitted through spores that are nearly invisible to the naked eye, it can be blown in on the wind, carried in on clothing, hands or tools. Here are some things you can do after you find Basil Downy Mildew in your garden.[图片]Remove Infected Plants Basil that has become infected with Downy Mildew may have a yellowish appearance, similar to a nutritional problem. The leaves turn yellow and fall off, while the stems wither, and the plant eventually dies. The most common symptom is the dusty spots, actually spores, that are located on the bottoms of the leaves. If you want a definitive diagnosis, you can bring an affected leaf to your local County Extension office for identification. Carefully pinch off a leaf and place it in a ziploc baggie for transport.[图片]Once you are certain that it is Downy Mildew, cover the entire plant with a bag to prevent as much of the spores from being shaken off as possible. Pull up the entire plant and remove from garden area. Do not try to compost or try to remove only the visibly affected leaves. Both of these techniques can result in the spread of the spores. Do not save your basil seeds from any part of that year's crop. The spores can infect the seeds and affect the following year's plants.[图片]Will It Stay In My Soil? Yes. The disease can stay viable for many years in the soil. Some experts say that the spores can stay viable for 8 years or more. If nothing else, rotate your crop of basil and plant in an entirely new location for the next season.[图片]Is Basil Poisonous That Has Downy Mildew? In a word, no. However, it is not advisable to eat leaves that are clearly affected. When you first notice signs of BDM, it is best to remove the entire plant and make pesto out of all the healthy leaves. Because basil grows so fast, quick removal and starting new plants in a new location is the best way to prevent spreading spores.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
What does one do to treat "fire blight" on Bradford pear trees? And what exactly is this horrible-sounding problem? No good can come, surely, from a condition that unites those two ominous words, given the destructive power of fire and the downcast mood evoked by "blight" (which, in the general sense, is defined as any cause of impairment, destruction, ruin, or frustration).[图片]A reader wrote in to inquire about just this problem. "The flowers on my Bradford pear trees turned black this year, and the new growth has died," he scribed. "The ends of the limbs are dead. What is wrong? Is this some sort of disease? And if so, how should I treat it?"[图片]What Is Fire Blight, Exactly? The symptoms that the reader reports indicate fire blight. Before you learn what to do about it, let's explore precisely what it is. Fire blight (sometimes spelled as one word) is a bacterial disease. The type of bacterium that causes it has the Latin name of Erwinia amylovora. The disease attacks trees and bushes in the rose family. If you have not been introduced to the rose family, please note that this designation does not refer simply to the fragrant rose bushes with which you have probably been familiar since childhood. Both apple trees and pear trees belong to this plant family, for example.[图片]Not only do the pear trees grown for their edible fruit succumb to fire blight, but also ornamental types such as 'Aristocrat' pear trees. While Bradford pear trees are relatively resistant to fire blight, that does not mean that they are totally immune to it (especially in warmer climates). Blackened flowers are an indication of fire blight. Fire blight bacteria can move down a branch and form a canker; it can eventually kill the branch or even the entire specimen. Remember that, since bacteria is at the root of the problem, treatment with a fungicide will have no effect on fire blight.[图片]What to Do About Fire Blight on Bradford Pear Trees Taking care of fire blight DIY-style is somewhat problematic, according to the University of California. They write, “Copper products are the only materials available to homeowners for fire blight control, and they often don’t provide adequate control even with multiple applications.” They suggest that some good can be done by a weak “Bordeaux mixture or other copper product applied several times as blossoms open,” but they go on to say that this will not solve your fire blight problem entirely.[图片]Have an arborist look at your Bradford pear tree if it is infested with fire blight. The disease can be treated if it is caught in time. An arborist will locate, prune off and dispose of the affected branches to stop the spread of the bacteria. As professionals, arborists also have access to sprays to which the average homeowner would not have access. An arborist may elect to use a bactericide (with streptomycin sulfate) on your Bradford pear tree to control fire blight.
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Dummer. ゛☀
2017年09月14日
Dummer. ゛☀
Fusarium wilt (foo-zair-ee-um) is caused by the fungus Fusarium oxysporum f.sp. lycopersici. Fusarium wilt is found worldwide and even resistant tomato varieties may be affected. The fungus is soil borne and makes its way into the plant through the roots. Once inside, it clogs and blocks the xylem, the tissue that moves water and some nutrients through the plant, preventing water from traveling up the stem and out into the branches and leaves.[图片]It may not kill your tomato plants, but they won't be very productive. Species of Fusarium can infect many plants including: potatoes, peppers, eggplants, legumes and bananas. Symptoms of Verticillium wilt can be very similar to Fusarium wilt.[图片]What Causes Fusarium Wilt? The Fusarium wilt pathogen is soil borne and can remain in infected soil for years. It can also be carried and transmitted in multiple ways, like: infected seed seedlings from infected soil the bottom of shoes shovels and equipment used in infected soil infected soil blown into the garden Ideal conditions for Fusarium wilt include warm, dry weather and acidic soil pH (5.0 - 5.6) There are tomato varieties that are resistant to fusarium wilt, but if they are weakened by root-knot nematode, they become more susceptible to it. Plants infected with Fusarium wilt will be stunted and the earlier they are infected, them more severe the stunting. Keep reading for more photos and descriptions of Fusarium Wilt symptoms and how to control it.[图片]Symptoms of Fusarium Wilt on Tomatoes Fusarium wilt can sometimes be confused with other wilts, but here are some symptoms to help you identify it in tomatoes: Wilting The plants will literally wilt. Often it starts with a single leaf or shoot, near the top of the plant. It will recover at night, when temperatures are cooler, but as it progresses, the entire plant will wilt and not recover. Watering does not make a difference. Yellowing Lower leaves will turn yellow, often starting on only one side. As with the wilting, the yellowing will gradually move up the plant. Dry Leaves The wilted leaves will dry out and fall off. Discolored Stem If you cut open the stem length-wise you will see dark brown streaks.[图片]Management and Control of Fusarium Wilt of Tomatoes There is no cure for Fusarium and since it persists in the soil for years, it can be very hard to eradicate. Here are some measures to help you control it. Resistant Varieties - If you've had problems with Fusarium wilt, you would be wise to stick with resistant varieties. Seed packets and many seedlings will be labeled with their resistance to various diseases. You could also consult a seed catalog for choices. Sterile Potting Soil - If you are starting your own seedlings, begin with a sterile soilless potting mix.[图片]Raise the Soil pH - Apply lime to the soil in your garden, to bring the pH up into the neutral range of about 6.5 - 7.0. Control Nematodes - Since root-knot nematodes can lessen resistance to Fusarium wilt, don't let nematode populations build up in your soil. Don't Cultivate - Avoid injuring plants' roots by not using a hoe or cultivator around your tomato plants. Damaged roots are entry points for the pathogen.[图片]Disinfect Tools - Clean all tools that may have come in contact with infected soil and make it a habit to regularly clean and disinfect your garden tools. Rotate Your Crops - Since the pathogen can persist in the soil for years, you will have to find another area to plant your tomatoes. A 5 to 7 year rotation is recommended, but that does not guarantee the pathogen will be entirely gone.
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玲儿
2017年09月13日
玲儿
ヒメヒオウギの育て方・栽培方法 育て方のポイント 栽培環境・日当たり・置き場 冬に温暖で日照の多い場所が適します。凍らないよう注意し、寒地では防寒対策が必要です。栽培は一般的なフリージアに準じ、関東地方以西の太平洋側では栽培しやすく、株もよくふえます。半日陰や、あまり日当たりのよくない場所でも栽培可能ですが、徒長しやすく、花数も少なくなります。 水やり 3月から5月の成長期、発蕾期、開花期は極端に乾かさないよう、用土が乾き始めたらたっぷりと水を与えます。開花後は必要なく、鉢植えの場合も徐々に乾燥させていきます。夏の休眠中は水を与えませんが、雨が当たっても大丈夫です。10月ごろから、用土の乾き具合を見ながら少しずつ水やりを開始します。 [图片]肥料 ほとんど必要ないくらいですが、3月から4月に薄い液体肥料を3～5回施すと生育がよく、花も多く咲きます。 病気と害虫 病気：ほとんど見られません。 害虫：アブラムシ アブラムシがつくことがあるので、見つけしだい防除します。 用土（鉢植え） 水はけのよいものであれば、特に選びません。一般的な草花用培養土のほか、赤玉土小粒7、腐葉土3の配合土も利用できます。 [图片]植えつけ、 植え替え 植えつけ：9月下旬から11月に球根を植えつけます。3号鉢に3球くらいが目安です。凍らないところであれば庭植えもできます。早く植えすぎると葉が大きく茂り、霜の害も受けやすくなります。凍霜害の心配がある場合は、冬は鉢植えにして室内の窓辺で管理します。12月から早春の植えつけも可能で、充実した大きな球根であれば春植えでも開花します。 植え替え：秋、早めに球根を掘り上げて、新しい用土に植え替えます。または、鉢から抜いたまま一回り大きな鉢に植えて育てることもできます。 [图片]ふやし方 分球：自然に分球してよくふえます。 タネまき：タネは2mmくらいと大きく、秋にまくと翌春には開花します。 主な作業 花がら摘み：こぼれダネでもふえるので、株をふやしたくないときは、花がらを早めに切り取ります。
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
One day your clematis vine is thriving and ready to flower. The next day it’s withering before your eyes. What happened? Chances are it’s a fairly common fungus that affects clematis plants, called clematis wilt. Clematis wilt can kill the entire top of your clematis vine, but the roots should still survive. Here's how to identify this quick spreading disease and what you can do about it.[图片]What Does Clematis Wilt Look Like? Clematis wilt is a fungus disease (Ascochyta clematidina) that is also sometimes referred to as clematis leaf and stem spot. Clematis wilt causes the foliage and stems of your clematis vine to dry and whither, possibly even turning black. You may start to see reddish lesions along the stems, but the onset and spread of clematis wilt can be quick. That means you may not have any warning before an entire clematis vine turns brown. However it’s not unheard of for only a few stems to be affected, so if you see sudden discoloring, take heed.[图片]What Causes Clematis Wilt? Clematis wilt is spread by spores that probably remained in the area on the debris of last year's vines, or possibly were blown in on the wind, from another nearby clematis plant. Like most fugal diseases, it is more prevalent in damp or humid weather. If your clematis vine is thick and tangled and remains wet well into the day, it will be even more prone to attack. On older clematis plants, the woody portion near the ground is often the first area affected. It may also be the area where the spores over-wintered. Once affected, the plant begins to die back because the fungus cuts off its vascular, or circulatory, system and no water can be carried through the plant. Left untreated, clematis wilt will spread throughout the plant and can kill a heavily infested plant.[图片]What to Do for Affected Plants The good news is that clematis plants can recover from wilt, because it does not attack their root system. However, the bad news is that you can lose the entire top growth of your vine, during flowering time. To give your clematis the best chance of surviving clematis wilt, at the first sign of withering or drying, cut the affected stems back to ground level. It sounds severe, but it can save your plant. Dispose of the cuttings somewhere other than the compost.[图片]Since the roots were not affected, new shoots should emerge from the base shortly after cutting. If your plant does not re-sprout within a few weeks, don't give up. Washington State University Extension’s fact sheet said “One resource on this subject states that renewed shoots can appear up to three years after the problem, so do not lose heart if this happens.” After pruning back the diseased vine, keep the clematis roots watered, even if there is no top growth. How to Help Prevent Clematis Wilt from Coming Back To lessen the chance of clematis wilt re-infesting next year, remove all remaining vine and leaf growth in the fall and dispose of it outside of the garden and somewhere other than your compost bin. The fungus can easily over-winter in the dead foliage.[图片]If you wish to use a preventative fungicide, sulfur is recommended. Spray in the spring, when new growth first appears. Are All Clematis Susceptible to Clematis Wilt? To some degree, yes, clematis wilt can attack any type of clematis. The larger flowered varieties are most prone, while some of the smaller flowering varieties, like Clematis alpina and Clematis viticella, show better resistance. There is also some evidence that the older and better established a plant is, the less likely it is to become infected, but it's no guarantee. The best you can do is keep your plant in good health, prune your type of clematis when you should, and be on the alert.
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