Questions on: Willow
Ron Smith, Horticulturist, NDSU Extension Service
Q: One of my weeping pussy willow trees looks like it has some sort of blight. The leaves are shriveling and drying up as if the tree is not getting enough water. Is there any salvation for this tree? When it was planted, this was a very healthy specimen and plenty of peat and root starter was used. I have been giving the tree calcium to slow the fungus that is attacking it. This has seemed to work a little bit. What fungicide should I purchase from my local nursery? I do know that my local retail store has Streptomycin, which usually is used for fire blight. (Niagara Falls, N.Y.)
A: Try a Bordeaux mixture to see if that arrests the progress of the disease. Streptomycin is strictly for fire blight bacteria and shouldn't be used off label.
Q: We purchased a willow that has grown into a lovely tree. We live in the desert. I faithfully feed and water the tree, but last year I noticed it was turning yellow and loosing leaves. I can't find any bugs, sawdust or sap, but I have found some holes on the trunk and branches. Do you have any idea what this is? Can I help this tree? I have read your column and am afraid you are going to tell me the problem is borers. (Deming, N.M.)
A: This sounds like poplar borer damage. See if you can locate an insecticide that is sold under the Bayer brand name as "Bayer Advanced Insect Control for Trees and Shrubs." It may be too late, but willows are pretty tough trees and have been known to bounce back almost from the dead.
Q: I have 12 protected willow trees on a plot of land that I own. I need to build a house on the land so that I can sell the plot. One tree is in the way of me getting permission. The tree in question is a bit battered and worn. What is the best way to kill the tree without cutting it down? You mentioned that there are ways. Could you give me the name of the best products, even if they are not legal? Here in England, once the tree is dead it can be removed and it doesn’t matter how it died. Thank you for your time. (England)
A: You can use chemicals or go the nonchemical way. The decision as to which method to use is yours to make. A nonchemical way is girdling. If the trees in England have not begun leafing out or are just starting to, now is the perfect time to girdle a tree. Remove the bark in a circle around the base of the tree in a band that is at least 2 to 3 inches wide. Be sure the cambium (green tissue that will be evident when the bark is removed) is completely disrupted by scraping it down to the xylem (wood) of the tree. This action disrupts the phloem, which is responsible for the movement of the nutrients to the top of the tree. This action starves the tree to death. The tree will still leaf out this spring, but just barely. If the tree is in full leaf, it still will die, but it will take longer. It should be completely dead by next spring. The chemical method is to use an herbicide that is labeled for broadleaf woody plants and inject it into the base of the tree. You should get someone who is licensed to do this because I don't know what is considered a restricted-use pesticide in England. Willows don't give up easily, so suckering from the root system probably will happen. Good luck!
Q: My late father and I planted a small weeping willow tree about eight or nine years ago. It has done very well, but I noticed last fall that the leaves had little, black spots. Winter came and the leaves fell off. This spring a lot of the limbs look dead. Am I losing my beautiful willow tree? I am willing to do whatever I need to do to save this meaningful tree. I cannot bear the thought of losing it. I live in Pham, Ala. It does get very hot here during the summer, but my dad made sure that we planted the tree in a spot that would get and retain a lot of water. (e-mail reference)
A: I can almost guarantee you that the willow is not completely dead. Be a little more patient to see what leafs out in the next week or two. If what you see is not to your liking, you can harvest some of the green, leafed-out wood, stick it in the ground, water it regularly and watch it grow. Check some of the stems near the trunk of the tree by scratching the bark with your thumbnail to see if the cambium is still green underneath. If it is, very likely a cutting from that branch will root for you. Willows that have been around as long as yours usually don't die outright, but are plagued with any number of canker and leaf spot fungus diseases that kill them bit by bit. I've seen willows that should be dead, but still are sending out new sucker growth along the main trunk.
Q: We planted a weeping willow late last summer. While we were gone on vacation, it got hotter than we expected. Some of the leaves turned yellow and fell off. We are coming into spring now here in southwestern Wisconsin. The tree made the winter with a nice yellow color on the trunk and halfway out each limb. Some limbs are completely brown, while some limbs show small buds halfway out the limb. Do I cut the limbs back to where the buds stop? Do I cut the limbs without buds at the trunk? (e-mail reference)
A: Go for it, before the heat, humidity and bugs make cutting the limbs a real chore!
Q: I planted a corkscrew willow tree two years ago, but it is not growing very fast. The tree is healthy and so are the leaves. Is there anything I can do to help it grow? (e-mail reference)
A: Try fertilizer, but not the stake type. Is it getting ample water and sunlight? Is there competition from nearby plantings? Also, try loosening the soil around the tree. These are all the suggestions I can give you at this point.
Q: I am thinking of purchasing a dwarf weeping pussy willow tree for my small flower garden. I know that regular willow trees are very invasive to water lines and septic systems. Are the dwarf types also invasive? I want a small, ornamental tree for the spot in my garden. Any suggestions? (e-mail reference)
A: Where in the world is this spot you are talking about? Without more detailed information as to where you are, all I can tell you is to go ahead and use the pussy willow. It gets about 6 to 10 feet tall and is not known to have invasive roots. This is assuming that your location is within the hardiness zone range of this plant.
Q: I have a large willow tree in my backyard. I am considering building a stone ring around the base and then putting a couple of feet of topsoil in it to create a flower garden. I feel this will help cover the large exposed roots and cut down on the weed trimming. Is this OK? Will it expose the trunk or roots to rot? (e-mail reference)
A: Willow is one of the more tolerant species to this kind of treatment, so with some modification, you may be able to get away with this. You will need to build a wall around the tree trunk to keep the soil from the trunk. Give yourself a clearance of at least 12 to 18 inches. Spread sandy loam over the area you want to turn into a garden. You will need to wall or edge the area in some way to keep the soil contained. Do not use more than 6 inches of soil. The feeder roots are out to or beyond the dripline of the tree, so the impact will be minimal.
Q: I have a very large, old weeping willow tree near my house. A lot of big roots have surfaced in the lawn. To keep from breaking the mower blades, I decided to mulch over the roots and build the soil to plant other things around the base of the tree. However, someone told me that mulching the exposed roots would kill the tree and it could fall on my house. I can't believe this is true, but it could be. If not, do you have any suggestions on what would be good things to plant under the tree? Do I need to remove the mulch? (e-mail reference)
A: Some soil and mulch over the roots of a willow tree will not hurt the tree unless you use excessive mulch. I suggest a sandy loam with ample organic matter added, such as peat moss. Do not cover more than 6 inches of the roots. Do not go against the tree's trunk. Leave about 6 to 8 inches clear of any soil or mulch covering the trunk.
When topsoil is dumped to a depth of 18 to 24 inches and up against the trunk is when problems develop that could threaten the safety of the tree.
Q: We have what I believe is a twisted or corkscrew willow on our property. Sadly, the tree seems to be dying. It has branches from the core that appear to be dying. I love this tree. Is this a tree that should not be planted in our zone? Our backyard does have underground sprinkling. Is this a problem? Do I remove the tree and replace it? What would be a good replacement? (Saint Cloud, Minn.)
A: The corkscrew willow is hardy enough to grow in your area. The moisture content of the soil shouldn't be a problem, but the direct impact of the water from the sprinkler system could be the cause of the problem. You can replace this tree with another one just like it, but have the irrigation system checked out before doing so. If the water is spraying directly onto the tree, have the sprinkler heads adjusted.
Q: I have a willow tree with a large hole in the base of the trunk. Should I remove the tree or do you think it can be saved? The tree is about 35 years old and about 50 feet tall. I'm concerned about it possibly falling on my home. (e-mail reference)
A: When willows get that old and have rot taking place at the base of the trunk, you are better off having them removed before they collapse on your home or someone in the area. Be sure the tree service is competent, certified, bonded and most importantly, insured.
Q: I have a very large weeping willow in my backyard that is very near my house, but I love the tree. We are adding on to the house, so I'm wondering what chance it has of living if some roots are cut during construction. How can we help the tree during construction? (Moorhead, Minn.)
A: Discuss the tree's welfare with the contractor so he or she is aware of your concern. You or the contractor needs to erect a protective fence around the tree as far away from the trunk as possible, but still allowing the construction work to be carried on. When the roots have to be removed, make the final cut with a saw or loppers. A saw or loppers will give you a straight, clean wound and not a jagged cut. Do not allow any waste soil or construction debris to accumulate under the tree's canopy. Do no allow any heavy equipment to run under the tree's canopy without putting down sheets of plywood or steel plates to keep the soil from being compacted. If any branches are going to be in the way of the construction activity, have them professionally pruned before any construction equipment gets a chance to damage them.
Q: Our weeping willow has several round bulges/ knots in various places. Some are an inch or so across, others are about 3 inches. (e-mail reference)
A: Those bumps or bulges could be cysts formed by insects or midge having laid eggs at the trouble spots. The eggs cause cell proliferation in the tree, which surrounds the developing larvae. Cut a bulge open and see what it contains. Usually, this is nothing to worry about.
Q: I bought two weeping pussy willow trees (salix caprea pendula). Will I have any luck growing them here in Hazen? I also would like information on their care in the summer and winter and how to grow them on my own. (e-mail reference)
A: These are not the true pussy willows that like continuously moist conditions. They will do well in a drier location. The trees are marginally hardy for your area. In fact, I'll be surprised if they make it through a typical Hazen winter unless you provide ample protection before everything freezes up.
Q: We just bought a weeping willow tree. We have planted it in the front corner of our yard where water tends to build up when it rains. My husband's grandmother says planting it there will cause 20 years of weeping for the person who planted it and the roots will grow everywhere. Our septic tank is in the backyard, but the lines are parallel to the tree and about 30 yards away. We also have an above-ground pool behind the house. Is the tree OK where we have it or do we need to move or get rid of it? (e-mail reference)
A: Your husband's grandmother is right on! Weeping willows, in my opinion, have no place in typical residential property settings. The roots grow everywhere and the tree is an "expert" at producing lots of kindling wood once it gets started. They look and do great along river banks, edges of ponds or as a source of frustration next to golf course fairways. In my opinion, get rid of it!
Q: I have an old willow tree in my yard. This year there were many dead limbs and the bark was peeling off. We pulled off the bark and found many little bugs that we call pill or roly-poly bugs. When you touch the bugs, they curl up in a little ball. The bugs look like they have sectional bodies. What can I do to keep these bugs away? (e-mail reference)
A: Get rid of the rotting willow! The bugs are detritus feeders that eat decaying organic matter. The willow apparently has an abundance of decaying matter. If the tree is important to you, have an International Society of Arboriculture certified arborist inspect the tree to determine if the tree can be saved and look for other possible insect and disease problems.
Q: We've recently purchased a home with a willow tree that was planted too close to the house and water lines. What is the best way to kill the root system once the tree is removed? (e-mail reference)
A: I would have the arborist also grind the stump out. Ask to have the tree taken down about two weeks after it has leafed out. Then have the arborist grind the stump down below ground level. This way, the tree will have expended much of its stored energy with the spring flush of growth. Any sprouts that grow can be controlled as broadleaf weeds by applications of a herbicide containing dicamba.
Q: Do you know the Latin name for the corkscrew plant? Will it grow in Zone 3? (e-mail reference)
A: You probably are referring to the corkscrew willow, Salix matsudana Tortuosa. It is not hardy in Zone 3. If used, it should be planted in a protected location. Sometimes, one can gain a hardiness zone or two using good microclimate manipulation.
Q: I have a weeping willow that I planted last July. It was growing very well and getting a lot of water. Then I noticed some irregular borders around some of the leaves, but only found one grasshopper and no other insects. All of the leaves started to turn yellow and fall off. There was a sawdust consistency to some shavings, which were medium brown and occurring at the joints of the tree branches. Three branches died and had to be removed. Do you have any recommendations? (e-mail reference)
A: It’s bad news. The problem sounds like the tree has been invaded by borers. At this stage of the tree's life, fighting it is not worth the effort. Yank the tree out and begin again. Next time, carefully inspect the tree for borer or other destructive insect activity before planting.
Q: I planted a weeping willow in my front yard about four years ago. It has gotten large really fast. I am thinking about heavy pruning or removing it. It is planted about 15 to 20 feet from my water supply and sewage lines. Is this a safe distance or should I take it out before things get ugly? (e-mail reference)
A: Taking the tree out would rob your landscape of the beauty this tree contributes, but the roots can become a problem anywhere there is any leakage in a sewer or water line. You could have a root barrier installed by a competent landscape contractor. The barrier would keep the roots at a safe distance and not impede the natural flow of water across your property and through the soil.
Q: My wife and I just bought a new home. It has a lovely corkscrew willow in the front. Unfortunately, the person doing our lawn trimmed off most of the lower branches that where corkscrewing! He trimmed high, so the lower branches are now straight and narrow and all the corkscrews are on top. Of course, this ruins the look. Will new growth occur on the lower branches in the spring? Is there anything we can do to help it? (e-mail reference)
A: Your inquiry reinforces my contention that pruning is definitely an art and a science. One without the other leads to what you described. It may come back if there wasnt too much pruned off. In other words, if he didn't remove the grafted stock, which it sounds like he didn't, the plant should set out some new buds this spring that will have the corkscrew character that you desire. If it doesn't appear that is going to happen, then nip off the terminal bud back to the first lateral bud to stimulate lateral bud breaking further down the stem.
Q: I have a large willow tree in my back yard. For some reason this year, it is "raining" sappy, watery, clear-colored drops. It did not do this last year. What is it, why is it doing this and what can I do to stop it? (e-mail reference)
A: This is from insects and/or mites feeding on the foliage of the tree. They insert their stylet-type mouth parts and extract the juice from the foliage. It passes through their bodies and then is known as honeydew, which is a euphemism for insect poop! Get someone who knows what he or she is doing to spray the tree to bring these pests under control.
Q: I have a low area that has collected too much water this year and killed my four lilacs. Are there any flowering bushes that would do well in a bed that will stay wet in future years? (e-mail reference)
A: Yes, pussy willow or any of the willow species.
Q: I have a gigantic willow tree that is 45 years old. There are big roots or growths above the ground around the base of the tree. Would it be detrimental to the tree if I had some of those chipped away to make the ground level and mowing easier? Its hard mowing around the base. (e-mail reference)
A: Dont worry about hurting a willow that age! Do what needs to be done to make mowing easier.
Q: Growing up, we had a weeping willow in our yard that tore up our septic lines. I just received several pussy willows and would like to know if their roots are as bad as weeping willow roots. (e-mail reference)
A: While all willows have a proclivity for water-soaked soils, the pussy willow (Salix discolor) is not nearly as invasive as its more famous cousin. I still would not plant them over septic lines!
Q: I planted a weeping willow on the edge of a lake three years ago. The first year it did fine, but the next year it started losing limbs and leaves. I cut the dead limbs and used tree spikes to help it. This year, only two branches have leaves. I dont see any insects and it does not appear to be diseased. Do you have any suggestions? (e-mail reference)
A: It could be bacterial twig blight, crown gall, leaf blight, black canker, cytospora canker, anthracnose, scab, leaf spots, powdery mildew, rust, tar spot, aphids, imported willow leaf beetle, basket willow gall, mottled willow borer, scale or nematodes. In a nutshell, your tree is too far-gone. Sorry!
Q: We really enjoy your column. When is the best time to prune pussy willows and hazelnut bushes and how should it be done? I trimmed them before, but cannot remember if it was spring or fall when I did it. (Brookings, S.D.)
A: Thanks for the nice comments. Spring is the best time to trim them to the ground!
Q: I just purchased a weeping willow. How big will it get, how fast will it grow and should I plant it away from my other trees? (e-mail reference)
A: Is it a weeping willow or pussy willow? Ill assume the former. Willows will grow by feet a year, not inches, and will develop a spread equal to their height in many instances. They use a lot of water. If you have an area that tends to remain moist, it would be a perfect spot. Willows also are famous for producing kindling as they age, so be prepared for that little chore.
Q: I would like to grow some new willow trees from cuttings. How do I get the cuttings to root? I tried cutting new growth at an angle and putting it in water with root starter, but it didnt work. Im not sure why because I have used this method successfully on ivy and wisteria. (e-mail reference)
A: Willows have what are known as preformed root initials all along their stems. Cut off a healthy stem to the desired length, insert it into a moist medium and voila, roots form in no time.
A quick story about when I was a graduate student at the University of Georgia. I took a job on campus to put up a temporary animal pen using logs stuck in the ground and then laced with barbed wire. Later that season, a couple of the logs started to sprout and also the roots at the base. The logs I was using, as it turned out, were willow logs.
Q: I have four weeping willows and have noticed the trees have boring, white larva, which causes the tree to loose leaves and weep a white substance from the holes. What can I use to control the larva? I understand the problems with willows, but dont mind tending to them. (e-mail reference)
A: Contact a local International Society of Arboriculture arborist to help you. The material that controls borers is a restricted-use pesticide and only can be applied by qualified individuals. You need to get on this as soon as possible so the treatment is scheduled at the right time for best control.
Q: We have a huge, twisted willow (all the small branches are twisted and bent) that seems to be under some sort of attack. I didnt realize that something had been eating away at the core of the main branch. I assumed it had just died and was rotting via microbial degradation of some sort. I cleaned out all of the dead wood and treated the tree with a typical wound dressing material. Yet, every few days, I can still find accumulating at the bottom of the hole what appear to be very uniform, small shavings or slivers of wood about a quarter-inch long. These slivers are intermixed with fine, dry wood dust. I have not seen an insect on the tree. Ive surface sprayed it with Malathion, Sevin and Diazinon, but there was no effect. Any ideas?
A: Sounds like a borer problem. All the topical applications of insecticides wont make a difference. If the tree is important to you, and I assume it is, contact an International Society of Arboriculture certified arborist to see if it can be saved. The arborist may be licensed for special injectable insecticides that may be able to stop the borer activity.
Q: We have about 50 American willow trees. I noticed the leaves are dropping on a few of them. There are many small black insects on the branches. They are about an eighth-inch long and seam to be eating large holes in the leaves. Can you tell me what they are and how to control these pests? Are the trees in danger of dying from this problem? (e-mail reference)
A: Willows are besieged by a vast array of insect and disease pests. Since the trees are not in flower and there is little chance of bee damage, I would spray a low-toxicity insecticide such as Insecticidal soap to see if you can reduce the population somewhat. Insecticidal soap is effective only if contact is made. If this doesnt do a satisfactory job, then try using Sevin or Malathion. I dont know what the insects are based on your description. It could be beetles of some sort. I doubt the trees are in danger of dying from this attack, but it will weaken the willows somewhat and open the door for other organisms to move in.
Q: My weeping willow is at least 40 to 50 feet tall and is 30 years old. Part of the tree hangs over my neighbors fence. I agreed to have the limbs that hang over her yard cut. I also want to top the tree so its even on each side. Should I have it cut in late fall or early spring? (e-mail reference)
A: Pruning is both an art and a science. While there are preferred times for pruning, one can prune anytime the tools are sharp. If you prune anything that appears diseased, dip the pruner in denatured alcohol and burn it off before making the next cut.
Q: We have three willows, two Wisconsin and one niobe golden. They are planted together in a flood plain. They have solid rock ledges about a foot and a half below the soil, which is extremely loamy clay and always wet. The roots have spread laterally a long way since they were planted. Two of the willows are fine, but one Wisconsin has yellowing leaves. The trunk seems to bulge out a foot above ground and the bark is lifting out and off for about another foot. The trunk tapers to slender below the loose bark. The bark peels off easily, is spongy and separating. The leaves of the other willow trees are bluish-green. The bad one has leaves that are olive green and distinctly yellow, but plentiful. A few smaller branches are pure green, with no yellow leaves. The leaves have been yellowish since late spring. (e-mail reference)
A: The use of any willow species should be tempered with the knowledge of the serious problems that exist in the form of diseases, insects, nematodes and aggressive root systems. Some of the more common diseases are bacterial twig blight, crown gall, leaf blight, black canker, cytospora canker, anthracnose, gray scab, leaf spots, and rust and tar spots. Insects that can cause damage include aphids, imported willow leaf beetle, pine cone gall, basket willow gall, willow lace bug, willow shoot saw fly, willow scurfy scale and nematodes. Like poplars, willows can damage driveways and sidewalks and they continuously litter by dropping branches and leaves. In spite of this litany of shortcomings, people still like to plant them. Willows, along with poplars, are considered a short-lived tree species because of all the problems. As to what could be wrong with your tree, Im guessing a canker at the base of the trunk, or a root-rot disease, such as armillaria fungus. Contact a certified International Society of Arboriculture arborist to inspect the tree. Only an on-site inspection by a knowledgeable individual can determine if the tree can be saved.
Q: We have an area on our property that has standing water every spring into summer. It usually dries up in the fall. Can we plant willow trees in this area? Will the standing water kill them? (Carrington, N.D.)
A: No problem if they are the traditional weeping or golden willows. They will love it!
Q: We recently purchased a home that has a large willow tree in the backyard. The roots are massive and extensive. I am planning to landscape the remainder of the yard and need to cover the roots as well as plant some other shrubs. Can I plant a ground cover under the tree to disguise the large roots? Will ground cloth under a planned deck prevent the root system for growing there? Is there a way to contain its growth? Its a lovely shade tree, but somewhat of a nuisance. Two of my neighbors have outdoor swimming pools and one has already asked to cut the overhanging branches. What can you advise? (e-mail reference)
A: Very large willow trees in residential back yards are extremely dominant features in the landscape. As much as you love the tree, you might be better off having it surgically removed by a professional arborist and replanting something more benign to your backyard setting. The tree does not age nicely in residential settings. The roots tend to follow water very well and it produces an abundance of kindling, usually on a weekly basis. Willows are host to a plethora of diseases and insects. Im afraid that you will end up being frustrated with your attempts to build a setting around it, only to have the tree taken down in a few years anyway. I have a neighbor who planted a weeping willow a few years ago in his backyard. He asked me what I thought after the planting was complete. What could I say? When young, they look great; but now it is just at the point of becoming a minor problem. I give it five more years before they start asking me what they can do about the problems that accompany the aging of the tree. To pontificate further, in our area there are lots of beautiful Colorado spruce that are in the wrong place on small residential properties, literally burying the house behind their massive sizes. We all share the shortcoming of not realizing what the cute little tree will grow to in 10 to 20 years. When it gets to that point, we are too attached to remove it until it threatens us physically or our insurance premiums get too high!
Q: I have a question about pussy willows. My bushes have red spots on the leaves. What can be done to get rid of the spots? (e-mail reference)
A: Most likely the plants have a rust fungus. Try a Bordeaux mixture. It will keep the fungus from spreading but will not cure what is already infected. The material is available at most garden centers.
Q: Down at the bottom of a hill is a run-off pond with some wild growth that will soon be cut back and mostly removed. I am thinking of planting a willow or two, but have heard that they are very dirty trees. Is there a type of willow that is showy but not dirty? Do you have other tree recommendations? (e-mail reference)
A: Willows are dirty if they are not taken care of. The same holds true for just about any tree species. Depending on where you live, there are poplars, quaking aspens, bald cypress and larch trees that could be planted in wet areas.
Q: My mom always had a pussy willow tree in her yard. Since we recently lost her, I wanted to plant one in my yard in her memory. I received some branches from a friend and they are currently in water to root. Is this the correct procedure? Does the tree need anything specific in terms of sun, food, etc.? (e-mail reference)
A: Willows generally need a lot of sun and water. Once the cuttings take root, you can transplant them to pots or directly into the ground outdoors. Be careful not to damage the fragile roots that developed in the water. Most willows will establish themselves directly in the soil from dormant hardwood cuttings. All you need to do is to cut a piece of a twig, at least 10 inches long, from a branch that's dormant, before bud break in the spring. Stick it in the ground with the buds pointing up. That is all you need to do. The farther it is in the ground, the better, as the cutting will initiate roots all along its length, where ever its in contact with the soil. Good luck! (JZ)
Q: We have a 17 foot corkscrew willow on a raised portion of our yard next to a waterfall and the entrance of our home. It is a gorgeous setting with a perfect look. Unfortunately, because of the position of our house, it catches north and south winds. Last winter the freezing winds caused some frost damage. The majority of the branches are now dead. Are there any similar trees that don't grow more than 20 feet tall with these characteristics that would be hardy for our region and the position it would sit? Where would we locate a tree like this? (Sioux Falls, S.D.)
A: There are a couple of different willows that grow to about 20 feet and should be hardy in your area. French pussy willow, Salix caprea, also called "goat willow," is hardy in Zones 4-8 (you're in zone 4). Pussy willow, Salix discolor, also called common pussy willow, is native to eastern North America and is hardy down to Zone 2. Flame willow, Salix flame, a hybrid willow that's hardy in Zones 3-6, has dense branching and a red-to-orange twig color in the winter. We have a windbreak with these here in Fargo and it's very effective (dense branches) and attractive in the winter. There are probably many others that I'm not aware of. All three of these willows are grown by Bailey Nurseries, a large wholesaler in St. Paul, Minn. Your local retail nursery or garden shop may have them in stock or could order them for you. Good luck with your trees! (JZ)
Q: The wind snapped the top off our weeping willow. Is there any hope for it? (E-mail reference)
A: It takes more than a mere broken top to wipe out a weeping willow. If it dies or is dead, let me know. It might not look pretty, but it should survive unless something else is wrong with it.
Q: I am thinking of buying a young pussy willow. My concern is the effect the roots may have on the rest of my small garden, especially my pond. (E-mail reference)
A: There are a couple of plants that are referred to as pussy willow such as salix caprea, also known as the goat willow, and the salix discolor, which is the true pussy willow. You have reason to be concerned if youre purchasing a true pussy willow. They are very susceptible to cankers and require almost continually moist soil in order to thrive. It is a poor addition to your landscape but is fascinating when found in the wild.
Q: We have a very large weeping willow in our front yard. In the past week or so, we have noticed two large "splits" in the bark. One of them is at least two to three feet long (almost from the ground to where the willow begins to branch out) and probably two inches wide, and an inch deep. Do you have any idea what could be the cause and whether or not we should be concerned? (Moorhead, Minn.)
A: Low temperatures can cause frost cracks in some trees. There is nothing you can do right now. This spring, check the cracks to be sure there is no decay in the wood. If not, then you have a sound tree that simply got "nipped" by Jack Frost. There are two things you can do. Dont do anything to the tree if the wood is sound and no decay is evident at the center. If there is decay, then it would be a good idea to consider the possibility of removing the tree if it is deemed a personal or property hazard. If the tree has sentimental value, or is not a threat in any way and you wish to keep it around, then drill holes through the crack every 12 inches with a 7/16-drill bit, and screw ½ inch rods through the cracks. If you choose to do nothing, what will likely happen (assuming a healthy tree) is the cracks will close up when spring arrives and reopen again the following winter when the temperatures dip into the negatives. Callous tissue would probably form over the edges (again assuming a healthy tree) and decay might get started in the center of the tree.
Q: I have a pussy willow tree that has some scale on it. It is similar to the color of the tree and appears to be taking over several large branches. The tree is about 8 years old and has grown very quickly. Should I remove all the infected branches? Is this an insect? (E-mail reference)
A: Yes to both questions. The insect is one that feeds with a piercing sucking mouthpart and in sufficient numbers can weaken a plant to the point of death. Remove all the bad branches as far back as possible. When new growth comes out next spring, monitor it carefully to be sure re infestation has not taken place. If they have begun to re invade, apply a systemic insecticide such as Orthene as soon as possible.
Q: I have an old weeping willow tree that has several holes in it. Birds and squirrels are constantly putting new holes in it for their nests. We have covered some holes with wood blocks. Is this the appropriate thing to do? I'm afraid that if the animals continue to nest in the tree, it will die. (E-mail reference)
A: Old willow trees are to birds and squirrels the same as old shoes are to household kittens, cozy things to get into. You would have a hard time trying to control all the activity that goes on in such a tree. You are better off allowing nature to take its course. In all my years as a horticulturist interested in trees, I can honestly say that I have never seen a willow tree completely killed off by anything, disease, insect, or otherwise! They can look terrible and have many dead branches and limbs but there is always some new growth taking place. I have cut a couple of old ones down and am amazed at the amount of animal life that had taken up residence.
Q: I just got a call about a weeping willow that is bleeding. When the sap or fluid squirts out, it's white and makes a sound. It's a large tree and the bleeding is occurring about five and one half feet above the ground. I remember that bleeding was a problem with the Chinese elm. What might be happening and is there something that can be done? (Ellendale, N.D.)
A: It's just high internal osmotic pressure, which is nothing to worry about.
Q: My yard is very damp with clay soil and lots of direct sunlight. The soil is soft for the first 12 inches then turns into hard clay. Would a weeping willow grow well under these conditions? (E-mail reference)
A: Yes it will. There are only two places that I know of where a weeping willow wont grow, in a blacktop parking lot and a desert environment.
Q: Im thinking spring and would like to know where I could find Salix planifolia or diamond willow. I have checked catalogs but found nothing. I know they grow by rivers and water but no one seems to know what they look like. (Tioga, N.D.)
A: Another go-around on diamond willow - willows are a taxonomic mess! Salix eriocephala is called the diamond willow, heart-leafed willow and the Missouri willow. It's also a botanical synonym for salix discolor, the pussy willow, glaucous willow, silver willow and for salix missouriensis. Salix missouriensis is a tree or shrub up to 45 feet tall and has pubescent branchlets and lanceolate leaves up to 6 inches long. It's native to Iowa and Nebraska, south to Kentucky and Missouri and grows in zone six. Salix missouriensis is closely related to S. rigida, and some researchers think it's no more than a form of the latter. S. rigida, also called S. lutea, is hardy in zone four but like the guy says on the commercial, "But wait there's more!" Another name for Salix missouriensis is S. cordata. This apparently is inseparable from S. lutea except for the latter having yellow twigs. To simplify things, let's assume Salix missouriensis, S. rigida, S. lutea, and S. cordata are all similar and can all be called diamond willow. So in that sense, diamond willow, in some form, will grow in North Dakota! What adds to the confusion is the common term "diamond-leaf willow" which is Salix planifolia. This is a shrub about 10 feet tall with purple branchlets and leaves up to 2 inches long. It will tolerate zone two conditions and should also grow in North Dakota. To finally answer your question, if the last is what you are looking for, then I'm sorry, I don't know where you can find this species. It isn't listed in the catalogs that I have. Try checking with a local nursery and see if they can locate it for you.
Q: I recently purchased a small pussy willow tree. It didn't come with instructions so could you tell me how much sun and water it needs? I live in Minnesota so Ill have to keep it inside until this spring. (E-mail reference)
A: I will assume it is a pussy willow tree so keep it in direct sunlight as much as possible while inside. Keep it well watered. When spring arrives, plant it in the wettest part of your yard or where you can keep water readily available to the plant. Depending on where you live in Minnesota, it may or may not survive. It is hardy to zone 4.
Q: This year I planted an approximately 8-foot-tall prairie cascade willow. It is doing just fine. Besides plenty of water, what else should I be doing to help it survive the winter? I put about 2- to 3-inch layer of wood mulch out to the drip line around that tree and all of my other trees. Is that too much mulch? Thanks in advance for your wisdom. (Minot, N.D.)
A: Not at all, just make sure the mulch is not touching the trunk. Leave about a two inch mulch-free zone. Also, I would suggest wrapping the trees to protect them from vole and rabbit damage.
Q: I have several willow trees along my septic lines. I have heard that the roots are very bad for the lines. Do they attack the lines because of the water? Should I get rid of them? (E-mail reference)
A: I would strongly suggest it! They love the nutrient-rich water that comes from such systems.
Q: Our willow tree has recently started to get spots on the leaves, then they turn yellow and fall off. Not just one or two, but quite a few leaves. Also there are a few branches on the tree that never got leaves on them this year. They appear to be dead and may need to be taken off. Do you have any idea what could be causing this? The tree was very healthy and hearty for a couple years and now it just doesn't look right. Could it be a fungus? If so how should I treat it? (E-mail reference)
A: The problem is the species. Willows are a plant pathologist's dictionary of diseases and an entomologist's collection of insect problems! The tree is a perpetual problem as it matures on residential properties. You can spray it with Bordeaux mixture for diseases and malathion for insects on a regular basis and it will still die. All you can do is delay the inevitable with a continuous care program until you cannot stand it any longer and have the plant removed.
Q: I have a weeping willow tree and two purple leaf plum trees that I would love to get more trees from. I dont know how or even what it is called but I sure hope it could be done. I just would love to start some new trees from my existing ones. (E-mail reference)
A: Willow trees are very easy to propagate. Simply take some branches about pencil size or larger, about 9 to 12 inches long, and insert them into a sandy loam mixture, keeping them moist until a substantial root system develops. Purple leaf plums are not going to be quite as easy. Take cuttings in early June and try rooting them in the same media but under a mist system. If you can, get some rooting hormone powder and dip the cuttings into it before sticking. If these fail, don't fret; many before you have tried and failed. If fruit is available, remove the hard outer husk and plant this fall where you want them to grow.
Q: We have a large laurel willow in our yard that is about 30 feet tall. Beginning last summer, the leaves were much smaller and the tree started losing its branches in any type of high wind. They just snap off and fall to the ground. During the high winds on Feb. 11 the yard was full of willow branches that broke off the tree. Some of these branches are 2 inches in diameter, but snap like balsa wood. Should we have the tree removed? I am concerned that it may fall onto the house. (Fargo, N.D.)
A: I strongly urge that course of action. The tree is dead or dying and obviously has deadwood throughout. Better to be rid of it than to be picking up branches out of your living room or bedroom!
Q: We have a large weeping willow tree that is about 9 years old. This spring it got nice leaves. Now lots of the little weeping branches have lost their leaves. We have had some very strong gusty winds, but that has not bothered it before. Is there an insect that loves to eat on the pretty weeping willows? (Platte, S.D.)
A: Unfortunately, there are a host of insects and diseases that "love" the weeping willow! My suspicion is that it is one of the many canker diseases that afflict this species. If it were insects their presence would be fairly obvious.
Q: In early May you had an inquiry about diamond willow. I find it hard to believe that you hadnt heard of this willow. It makes very colorful canes and walking sticks. I looked up diamond willow in my copy of O. A. Stevens and it stated the botanical name as Salix missouriensis. Another source, Flora of the Great Plains, said the correct name was Salix eriocephala Michx. (Napoleon, N.D.)
A: Yes - sometimes things get by me and I need to get informed from people like yourself. Thank you!
Q: We have a laurel leaf willow tree, which we planted about eight years ago. It did very well and had terrific leaves until about two years ago when the leaves were much smaller. This tree has about an 18-inch base and has been very healthy. About mid-summer some little leaves turn yellow and just drop off. At the same time the seed pockets, which used to fall off, start to pop open and spit cotton all over the grass. Can you tell me what is wrong with my tree and what I should do about it? (Beulah, N.D.)
A: I could see nothing wrong from a pathogenic standpoint, with the sample you sent in. I would suggest core aeration around and outside the dripline of the tree. You may also want to try vertical mulching around the tree as well. It could be as simple as soil compaction causing the problem after so many years. This treatment will at least give the tree a good opportunity to recover.
Q: I am interested in information on diamond willow. Specifically I would like to know when the best time is to cut it to prevent it from breaking or cracking. (E-mail reference, Valley City, N.D.)
A: I have heard of pussy willow, sharp-leaf willow, laurel willow, white willow, blue fox willow, wooly willow, and many more, but never the diamond willow. Please, if you can, give me a botanical name. Salix what? This highlights the problem with using common names, as they may or may not have a relationship to the same plant generically. That said, the best time to prune about 90 percent of the deciduous trees in our area is now, before leaf-out, and that should include the "diamond willow" as well.
Q: Please identify the cause of these red spots on my willow trees leaves. The tree appears healthy, is 15 years old and more than 20 feet tall. The spots have been present for the last four to five years. (Bismarck, N.D.)
A: The blister-like swellings on your willow are galls that are caused by mite activity feeding in early spring as the leaves unfold. Nothing to worry about, as the damage is only cosmetic.
Q. We bought our house 10 years ago after it had sat empty for several years. No one took care of the flower beds while it was empty. Apparently, the tulips reseeded themselves because every year since, tulips have been coming up all over the place. We never know where we'll be seeing new plants. Each spring brings a surprise! They usually come up in inconvenient places, but I haven't moved them because I'm not sure when would be the best time. If I wait until fall, I can't remember where they all are. I tried to mark some of them a couple of years ago, but grandkids didn't realize what the markers were and moved them. I also need to dig up some that I planted a couple of years ago that have multiplied and are much too thick.
On another note, I'd like to tell you about our pussy willow tree. I always wanted one and even though I knew it probably wouldn't survive, the price wasn't bad so I bought one. The first year we left it in the container because we couldn't agree where to plant it and buried the container in the ground on the east end of our garage. We planted it permanently in the spring of `96. It's now about 5 1/2 feet tall, bushy and covered with pussies. It spent the winter of `97 under a 10-foot snowbank and this past winter with no cover at all. I realize we may not have it for long, but we are sure enjoying it now! I snipped off a couple of branches that were near the ground about a month ago and brought them in, put them in some water so we could enjoy the pussies a little longer. Lo and behold, no pussies but leaves and roots. So I planted them in a flower pot and plan to plant them out when the weather settles a tish more.
We enjoy your columns both in the Farmers Forum and our Ransom County Gazette and have learned so much. You really should compile your columns into a book! (Stirum, N.D.)
A. Thanks for the nice newsy letter!
Move the tulips as the leaves yellow and can just about be separated from the bulb. Store them cool and dry until Labor Day, then plant where you want them.
Sounds like you are having fun with your pussy willows. Keep on trying.
Q: We got pounded with hail this spring and now my pussy
willow branches have holes in them with sawdust coming out of
them. Do I spray or remove the
branches? It may decimate the shrub if I have to remove all the branches. What do I do? (e-mail)
A: The pussy willow sounds like it has borers damaging it. If you can, cut the affected branches back and destroy them by burning or chipping--just get
them away from the plant. Spraying would do very little good at this time. Try to keep the plant growing vigorously with fertilizer and water, when
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