Questions on: Crab Apple
Ron Smith, Horticulturist, NDSU Extension Service
Q: I planted a chestnut crab last year. It has two central leaders with a narrow crotch about 18 inches off the ground. Should I prune it to a single, central leader? (e-mail reference)
A: Yes, but remove the weakest one.
Q: What is the tree with the fragrant white flowers? They are growing all over in Grand Forks. I'd like to plant some myself someday, but don't know what they are. (e-mail reference)
A: The tree could be spring snow flowering crab, Juneberry or flowering pears. If you can pick a small branch from one of them and bring it to the Grand Forks County horticulturist for positive identification, you would know for sure what it is you want to purchase.
Q: I have a crab tree in my yard that has two low branches that appear to be suckers or water sprouts (not sure of the difference). They do not look like normal branches because they come out and grow very close to the trunk. I know I should have dealt with this problem years ago, but what do I do now? Should I cut them off as close to the trunk as I can or leave them alone? (e-mail reference)
A: After you get done reading this, go out and cut those growths back flush to the trunk. I know of no reason why they should be left as is.
Q: We are about to start extensive building alterations. Sadly, a beautiful, mature crab apple will need to be removed. We would like to transplant the tree to another area in the garden. It is not a commonly found tree in our area, so no one seems to have enough knowledge about it. It would be sad to lose this lovely tree. We are at the end of our summer and moving into fall. Building will start within the next six weeks. (e-mail reference)
A: I assume you have something approaching a winter with freezing temperatures in your area. If so, after the tree drops its leaves, you can hire a tree spade operator to come in and move the tree to a more suitable location. If you can't wait that long before beginning construction, then wait as long as possible before moving it. Try to locate a tree spade operator who has a large, truck-mounted machine to do the work. A 66- or 90-inch would be best because you want to harvest as much of the root system as possible. If there are no tree spade operators in your part of the country, then you need to hire a nursery or landscape contracting company to come in and do a manual ball-and-burlap operation. It is more labor intensive and takes more time, so likely it will be more expensive. Get the prices nailed down before the digging starts. I doubt that anyone will guarantee the survival of the moved tree.
Q: I have a beautiful flowering crabapple tree in my front yard. It has been suggested to me that the roots might break up the drain from my house to the city sewer. Could you please describe the root system of flowering crabs in general? Are they mostly surface roots or are there deep tap roots? (e-mail reference)
A: In my past experiences of digging up old crabapple trees, I found the roots to be mostly surface, with one or two going deep. It depends on the crabapple rootstock and if the drain tiles are leaking water. In this modern day, very few, if any, drains leak, so the roots have no way of entering the system. Besides, most drains are down 4 feet or more. I promise you that I never have dug up any crabapple roots that deep! Usually the poplars and willows are the culprits that invade leaking tiles because of their aggressive roots.
Q: We have a new home with a mature crab apple tree that is heavily covered with sucker growth. Last year’s apple crop was very small and many apples were diseased. My question is about pruning. How much of the length of each sucker should I prune? How much should be removed? Should the tree be pruned in late spring as you said? (e-mail reference)
A: Excess sucker growth is not a good sign for the well-being of a tree. It is usually an indication the tree is in a state of serious decline. I was incorrect if I said that late spring is the time to remove the suckers. The suckers should be removed in early spring, before new growth begins. Pruning when the tree is in leaf opens it up to the roving pathogens that are going to get established in such a weakened tree. All sucker growth should be removed. You should prune the branches as needed, but do not remove more than 25 percent to 30 percent of the branching system per season. It is better to prune too little than too much. If you prune too much, it encourages more sucker growth.
Q: Is it OK to use cedar mulch with crabapple trees? I heard there is a possibility of cedar apple rust infection. If so, what would you recommend? (e-mail reference)
A: This shouldn't be a problem because the mulch goes into a composting or weathering process before being used. Also, the pathogen needs living tissue, which mulch is not.
Q: I have a crab apple that I want to move to the other side of our house. However, my husband is concerned about the roots growing into the foundation. (e-mail reference)
A: Unless the foundation is cracked and leaking, it should not be a problem. A lot of trees of this and other species have been planted close to foundations without causing a problem. With a roof overhang and better soil to mine outside the overhang, the roots have little opportunity to move toward the house because of soil, water and nutrient deficiencies. I suggest leaving the tree where it is unless you have another reason for wanting to move it.
Q: Is there any way to keep a flowering crab from producing apples? It's a good looking yard tree, but I absolutely despise all those useless, little, messy apples in my yard. (Rothsay, Minn.)
A: There are several products on the market that you spray in the early spring as the tree is in flower. None are 100 percent effective and it depends on the cultivar as well. Most sprays are hormonal in action, resulting in an abortion of the fruit. I've heard some people swear by the products and others swear at them! I gave up and took my crab apple down because I couldn't find anything that would control the fruit set, so good luck! Florel is the most known product available on the market and just may do the trick for you. Be sure to follow label directions.
Q: I just moved into a house that has two flowering crabs in the backyard (my mother told me that is what they are). They both look OK from a distance, but when you get closer, you can see little holes in the branches and bark. The holes look like someone has drilled into the bark. There also are little eggs on some of the leaves that ants are feeding on. I would like to know what kind of bug this is and what I can do to stop it. (e-mail reference)
A: This sounds like bark beetles, borers or possibly scale insects. You can send photos if you wish or get a product called Bayer Advanced Tree and Shrub Insect Control and use that as a drench around the base of the tree. The product is translocated systemically through the vascular system of the plants, killing the insects that may be feeding on the plants.
Q: I read your answers to questions about pruning crab trees. I just want to be sure I understand your answer about the timing. You said early spring, so that means before flowering. Will the trimmed branches blossom? (e-mail reference)
A: You are correct. Early spring means before the trees bloom or leaf out. The remaining branches should produce a nice show of flowers, unless the pruning was very severe.
Q: I am looking for a Web site that will show me exactly what flowering crab colors are available. I am looking for a dwarf variety to plant in my front yard. (e-mail reference)
A: Google some nursery Web sites, such Bailey's, Monrovia, and Jackson and Perkins. There should be something in one or all of them.
Q: I just received a prairiefire flowering crab tree. It is about 8 feet tall, but is in the same bucket as when it was purchased. It has started to flower profusely. When is the best time to plant this tree in the ground and what is the best way to do it? (e-mail reference)
A: Get it planted as soon as possible. If possible, hire a teen to assist you. An 8-foot tree in a bucket is too much to handle, unless you are into weightlifting! Dig the hole as deep as the container and twice as wide. Set the plant, container and all, into the hole. Make sure the surrounding soil is just even with the crown of the plant, which is where the stem becomes the root system. After that, carefully cut the container off (I assume it is a HD poly type), remove the sides, but leave the bottom on. Don't worry about the bottom part. Backfill with the soil removed, firm by hand and slowly soak the soil. Water it well once a week during the summer.
Q: I would like to ask two questions concerning flowering crabapple trees. I have one crabapple tree that is about four years old. The tree is beautiful, with dark pink flowers in the spring. I just noticed that the bark on the trunk is peeling. I haven't noticed this problem in past years, but really wasn't looking. Is this common or do I have a problem? The tree does have fruit on it and the buds are starting to emerge. Also, are there flowering crabapple trees that have early, mid and late-season bloom for succession in the landscape? (e-mail reference)
A: Many cultivars of crabapples have peeling or exfoliating bark as they mature. This is nothing to worry about. As to blooming sequence, most will bloom about the same time. About the only difference would be in the microclimate setting. Those having a northern exposure will bloom later than those with a southern exposure.
Q: When is the best time of year to trim a flowering crabapple tree? And how much do you trim back? Part of the top broke off in a bad storm last year, so now it looks out of balance. (e-mail reference)
A: Pruning can take place anytime before spring growth. Prune off no more than 25 percent to 30 percent of the total crown area. Clean up the area where there were some broken limbs to prevent disease or rot from setting in.
Q: I have a flowering crab that has overgrown the area it is planted in. I need to prune it. From what I have read, the best time to prune is late winter. How much can I prune off the tree without killing it? (e-mail reference)
A: You are correct in saying that late winter or early spring is a good time for pruning most deciduous trees, including flowering crabs. A basic rule of thumb is to prune no more than 25 percent to 30 percent of the total canopy during a growing season. This is because it would result in too much sucker growth that would literally negate your efforts for improvement pruning. If this is a tree that never has been pruned, don't yield to the temptation to get in there and "clean it up" from years of neglect! Remove the crossing-over branches, any that have "self-grafted" and any that are diseased, dead or damaged. In subsequent years, prune to open the crown for better air and sunlight penetration and more aesthetic appeal.
Q: We have two snow flowering crab apple trees and an autumn maple tree. I would like some information on how to prune these trees. I tried to find your Web site, but was unable to find it. Can I get the address so I don't need to bother you? (Webster, S.D.)
A: Go to Google and type in Hortiscope or you can type in the header www.ext.nodak.edu/extnews/hortiscope/contents.htm. That will take you to the opening page, where you can navigate to your heart's content. If you miss the publications listing, one of which shows proper pruning techniques, then go to www.ext.nodak.edu/extpubs/trees.htm. At that address, you will see the listings and can select H1036, "Pruning Trees and Shrubs."
Q: The crabapple trees that line the avenue in our neighborhood are looking very distressed. They bloomed gloriously this spring, but now look like they are dying. They had drooped leaves all summer. We have one in our yard that is in the same condition. Are they a lost cause or can they be saved? What do you recommend? (Fargo, N.D.)
A: It could be apple scab, which is a plant disease caused by the fungus Venturia inaequalis. It also could be a rust fungus known as cedar-apple rust. Both cause early defoliation. The rust fungus is more isolated, while the scab fungus is more universal in spread, so I believe this is what you are seeing. Clean up all the leaves and fruit this fall. Next spring, spray the trees with lime-sulfur while the trees are still dormant and again after leafing. Use a fungicide known as Captan. Repeat again in 10 to 14 days.
Q: I live in North Branch, Minn., which is right on the border of Zone 3 and 4. We bought a royalty crab tree from our local nursery eight years ago. It has beautiful foliage in the spring and early summer. However, it begins to lose its leaves in early July. Is there something wrong with the tree? Is there something we can do to prevent this from happening? Our neighbors have the same tree and problem. (e-mail reference)
A: This is likely a foliar disease known as apple scab. There is a lot of it going around this year. Spray the tree with a Bordeaux mixture for now and be sure to pick up all the fallen fruit and leaf litter this fall. Next spring, spray the tree with lime-sulfur while dormant to protect and “sanitize” the tree. As the foliage unfolds, spray with Funginex, a Bordeaux mixture or Captan fungicide.
Q: We have a flowering crabapple tree that shades a large portion of our house. It was here when we moved in 15 years ago. It bloomed profusely this spring, but it is already losing its leaves. What does this indicate? There are several yellow leaves on the tree that I suspect will soon fall. I would hate to have it die. What are your suggestions? (Sioux Falls, S.D.)
A: The tree is obviously subject to a leaf spot (likely scab) disease problem. It will take a lot more than this to kill the tree, but it will weaken it and make it vulnerable to other problems. You can spray with a Funginex or Bordeaux mixture right now to help prevent the spread of the spores to the uninfected growth. Clean up all leaf and fruit liter this fall. Next spring spray the tree with lime-sulfur before leafing occurs. As they open, spray with the aforementioned fungicides or Captan.
Q: We transplanted three flowering crab trees at a new house three years ago. They were 15 years old when we had them moved with a tree spade. They were moved in November. The next year they looked excellent. The following year about a third of the branches lost their leaves in the spring. In the fall, the bark on those branches looked like they were suffering from sun scorch or fire blister. Those branches were cut off last fall. This year I have noticed woodpeckers around the trees. Is there any hope for these trees? Can I cut the tops off the trees, leaving only the trunk, so new branches will sprout? (e-mail reference)
A: Cutting the tops off the trees is about the worst thing you can do to a tree and have it resemble anything that would be considered a real tree species. You are better off removing the trees, if you are not satisfied with the way they are growing. I assure you that moving crabapple trees that old left many roots behind. These trees put out extensive flare and feeder roots that make it difficult for them to survive transplanting. I suggest removing the trees and replanting. They grow quickly and you’ll be happier in the end.
Q: I have a client who has two old (likely hopa) crabapple trees. The trees looked normal to me, but the client mentioned that they are not putting out pink spring flowers like they used to. Could it be that the trees are simply going into decline? The leaves look clean at this time of year. (e-mail reference)
A: Ask the client when the trees were last pruned. That is often the problem. Intelligent pruning during a two- to three-year period will bring them back to their full show.
Q: We grew three crabapple trees from very small seedlings. One tree is now about 10 feet tall while the other two are about 6 feet. This is the third year that they have been in the ground, but we have had no blooms. The trees have not been pruned, except to remove some suckers. Is the absence of blooms normal or do we have to do something to promote blooms? (e-mail reference)
A: Hang in there for a couple more years! In some cases, it takes about five to six years for these trees to grow up enough to produce flowers.
Q: We have a crabapple that is too large. I know you are not supposed to prune in the summer, but it is blocking the light to my flowerbeds. Is there anything I could put on the parts I cut to avoid disease, or would you be totally against pruning at this time? Please help. (e-mail reference)
A: I am never totally against pruning anytime the tools are sharp and there is a realistic need to do so. The risk of disease is greater during the growing season than when dormant pruning. Prune whatever you need for satisfactory growth in the flowerbeds. Dip your pruning shears and saw in alcohol prior to pruning and between each pruning cut. No wound dressing is necessary or recommended.
Q: I have a flowering crabapple tree (I think) in my front yard. From the roots, there are little shoots sprouting up all over the yard. What do I do to stop that? (e-mail reference)
A: Prune them back to the root and get some Sucker Stopper RTU from a local garden center. Spray it on the pruned spots. It will not produce new suckers there again.
Q: I have had a flowering crab tree for four years, but it doesn’t seem to be growing. It flowers and gets berries, but doesn’t get any bigger. What can I do or is its growth stunted for some reason? (e-mail reference)
A: You might just have a dwarf cultivar that has reached mature size.
Q: My crabapple tree had been blooming nicely the past few years, but last year it didn’t get flowers. The leaves were eaten by inchworms. I sprayed the tree, but did not get any flowers this year. Can you please tell me why? (e-mail reference)
A: Flower buds have a different (lower) hardiness level than the leaf buds. It could be that the tree was in a state of vulnerability when the buds were about to open, so a cold snap may have killed the flower buds. With the information you have provided, that’s the best answer I can come up with.
Q: I planted a thunderchild crab apple tree on my front lawn last year. At the time, it was flowering and looked wonderful. This year the buds seem to be dry and brittle like they’ve been through a drought. When I touch them, they feel hard and there is no sign that a soft leaf is trying to poke through or open up. (e-mail reference)
A: It sounds like the parts you examined are dead. If this is true with the entire tree and there are no buds emerging, then the tree is likely finished.
Q: Is it bad to pick crab apples off a tree? (e-mail reference)
A: Who said it was? If it were, there would be thousands of us who would be committing this “bad” action! In what way is it supposed to be bad?
Q: We have a lovely crabapple tree in our backyard, but it has numerous shoots growing out of the bottom and elsewhere. Should the shoots be cut off? Is there a proper way of doing this? (e-mail reference)
A: Remove the water sprouts and suckers. They are not making a positive contribution to the vigor of the tree. Cut them off at their point of origin. Excessive sucker and water sprout growth is a possible indication of tree decline, so monitor the health of the tree through the growing season. Prune the tree in late winter or early spring.
Q: We have a crabapple tree that flowers nicely, but no longer produces fruit. It starts to loose some leaves in July. How can we help our tree before it is too late? (e-mail reference)
A: Get some apple scab protection spray on the tree immediately and repeat every seven to 10 days when the bees are not active. Spray until the fruit is about golf ball size. The materials to consider using include benomyl, mancozeb, Fore or Bordeaux mixture. Always clean up fallen fruit and leaf litter.
Q: I’ve got a crabapple tree that is growing very fast a few feet from my house. The upper branches are taller than the house and growing into the gutters. The tree is very V-shaped and looks top-heavy. I would like to reduce the height of the tree. Can I do it without “topping” the tree? (e-mail reference)
A: Cut the tree back to a lateral branch. That way you won’t “top” the tree. If you can make the lateral branch an outside one rather than an inside one, and do this when you prune every spring, the tree will tend to grow more horizontally.
Q: I am fairly new to the gardening world and have a question to ask about our thunderchild crabapple tree that we recently planted. It has developed three suckers quite near to and below the base of the soil line. How do I go about removing the suckers and what would happen if they aren’t removed? (e-mail reference)
A: Any sucker growth coming up from the base of the tree will simply rob the scion or budwood of the tree (top part) of nutrients. If they are not removed, the suckers will eventually takeover the tree. Cut them back to their origin, and spray the area with RTU (Ready To Use) Sucker Stopper, which should be available at a good garden supply store.
Q: I have a question about an old flowering crab tree. Each year, including this year, it has bloomed beautifully. The past few years we have noticed the bark is peeling, and after it blooms, the leaves begin to dry up and turn yellow. The tree drops about half or more of its leaves. It had a tremendous crop of berries the last two years, but only a few this year. I`m afraid it is old and dying. What do you think? (Lake Park , Minn.)
A: Old crabapple trees can have any number of pathogens or insects that cause the symptoms you describe. If the tree is important to you, I would suggest contacting a local International Society of Arboriculture certified arborist to make an accurate diagnosis and discuss a possible remedy.
Q: We planted a crab tree last year. It got blossoms this year and very small red fruit, but the leaves were very small. The tree looked fine except for the bare appearance because of the small leaves. Any clue as to why the leaves were so small? (e-mail reference)
A: It is the new growth that counts. Everything will even out with time, so don’t worry. The fruit will not get much larger because it can’t go beyond its genetic potential for size and color. Last year’s environmental setting probably had an impact on the leaf size of the older growth.
Q: I have a crabapple tree that is bearing a lot of fruit, but I can’t find anyone who can tell me when the fruit is ripe and ready to make jelly. (e-mail reference)
A: Without knowing where you live, the conventional wisdom is to wait until after the first frost. Generally, late August to early September is a good time.
Q: I have two flowering crabs in my backyard. They flowered beautifully this spring but then began to look sick. The berries and leaves had a rusty layer that could be rubbed off. Two other trees in my neighbor’s yard looked the same. (e-mail reference)
A: Sounds like cedar-apple rust. Clean the area thoroughly this fall and spray a lime-sulfur mixture early next spring while they are still dormant. Spray with a Bordeaux mixture after the leaves unfold. Repeat the fungicide spray again 30 days later. That should provide protection. In the meantime look for the offending alternate host, junipers. If you see an orange globular growth on the trees this fall or early next spring, pick them off and dispose of them. That is the source of infection on your crab-apple trees.
Q: Our beautiful flowering crab tree is not looking well. It flowered beautifully this spring, but its leaves turned brown and fell off. The trunk has a split in the bark the entire length of the tree. Can it be saved? (e-mail reference)
A: It doesn’t seem promising. I would suggest removal and replacement. Sorry.
Q: We had a prairiefire crab tree planted in our backyard last year. We were told it was very resistant to diseases, but the leaves are turning brown and falling off. The tree looks sick. We brought a branch back to the nursery, and we were told that the tree has been infected by spores from the arborvitae in our area. Can this be true or are they just trying to get out of replacing our tree? (e-mail reference)
A: Nice try, but it won’t work. They are probably thinking the problem is cedar-apple rust and the arborvitae is the alternate host. The alternate host to cedar-apple rust is the juniper, not the arborvitae, which is an entirely different species. There could very likely be some junipers in the area that are acting as the alternate host for this disease. If they are on your property, you can control that quite easily. It’s a problem if they are on someone else’s property. This disease can be controlled with a good spray program. Use lime-sulfur in early spring while the tree is still dormant. Use a Bordeaux mixture as the new leaves unfold, and again 10 days later.
Q: My crabapple tree is loaded with fruit and appears very healthy. Initially the fruit is clean, however as the fruit starts to grow, small black and/or dark brown spots start appearing on some of the apples. As the season progresses, these spots appear on most of the apples. The spots penetrate about an eighth inch deep into each apple, but don’t seem to affect the overall quality of the fruit. Is this apple scab, black rot or insects? I can’t believe insects could be so industrious that they could bore into hundreds of apples in such a short period. Also, you mentioned making apple sauce with crabapples. How do you core them or don’t you bother? (e-mail reference)
A: It is apple scab. It doesn’t affect the eating quality of the apples, just the aesthetics. Making applesauce is something my wife does with our dolgo crabapples. I am the beneficiary of her efforts, so I won’t attempt to tell you how to do it. You may want to contact someone in food and nutrition at NDSU and have them send you instructions.
Q: My crab apple tree has lots of apples but they don’t get very big. Right now the apples are the size of peas. Can I remove every other apple so that the remaining ones will get bigger? (e-mail reference)
A: That is a lot of work and probably won’t make any difference! The size is mostly determined by genetics, especially with crab apples.
Q: I planted two crabapple trees last fall in a new housing addition. They seemed to be doing fine until about three weeks ago. The dark pink looks like it has a white paint or coating on the trunk and a few of the branches. I also noticed some of the branches are bare. The white crabapple next to it now has the same symptoms. (e-mail reference)
A: It could be cottony cushion or some other species of scale insect. Take a twig with the infestation on it to a local nursery for confirmation. Purchase horticultural oil that will control these destructive pests. If they don't have the oil, see if they have a systemic insecticide that will do the job.
Q: We planted two prairie fire crab trees three weeks ago. They looked beautiful until two days ago. The leaves have turned yellow and are dropping off. There are still some green leaves toward the top of the trees. The trees have received plenty of water from rain and sprinkling. (e-mail reference)
A: They have probably been overwatered. You should never have the water from a sprinkler impacting directly on the foliage of a tree. The plant could have a leaf spot or rust fungus. Back off on the water or redirect a couple of sprinkler heads. Hopefully, you will be able to save the trees.
Q: I have three flowering crabs, one white and two red. Last spring the white and one red were loaded with flowers, more than I’ve ever seen in the 15 years I’ve had them. When the flowering was done, I noticed they were really thin on leaves. This spring they were dead. The other red one is okay. They are in a row within 20 feet of each other. What happened? Also, my Dutch elm is loaded with what might be seeds. They are small, round, flat pieces. I’ve had the tree for 20 years, but have never seen it like this before. It, like the flowering crabs the year before, has very few leaves on it. My other elms seem to be fine. It’s almost like they spent all their energy on flowers and seeds. (Hartford, S.D.)
A: When a tree puts on a heavy reproductive show, it is a pretty good indication it will soon die. The cause could be armillaria root rot. It happens to many people, including me. You should remove the trees as soon as possible and replace them with a different species.
Q: I have a radiant crab tree that was planted in the spring of 1999. It has been growing just fine, but it never has any blossoms or berries. (Harvey, N.D.)
A: I question whether it is a crabapple. If it is, it may not be a true radiant crabapple or a variety that is hardy enough for our area. You can try traumatic stimulation to get it to bloom next year. Avoid fertilizing with nitrogen. At the outer edge of the canopy, take a straight-edged spade and drive it into the soil as far as possible in four to six places. This will cut some of the roots and hopefully shock or stimulate the plant to go into a reproductive cycle. It may just be living too much of the good life and not have the motivation to go into a reproductive cycle.
Q: A couple of days ago my husband pruned, actually sawed off, two large branches from a flowering crab. Is there something we should put on the cut to protect the tree? (Mandan, N.D.)
A: If the tree is healthy and the cut was done properly, the wound will heal normally. If the tree is not healthy and the cut was done improperly, then all the dressing in the world won’t make a difference.
Q: I have two flowering crab trees we purchased in 2000. One is growing well while the other is still small (I am assuming I need to trim the growth at the bottom.). Neither tree has ever flowered, which is why I bought them in the first place. Please advise! (e-mail reference)
A: Be patient, don't fertilize and resist pruning. I promise they will flower!
Q: My yard was overgrown with mature trees, so I decided to kill the weakest looking one which was an old crab apple. Last fall I took down the branches leaving the tree seven feet tall. This spring, much to my surprise, the tree flowered on the few remaining small branches. I used a chain saw to girdle the tree about a quarter to a half inch deep all the way around the base. The poor thing has much more of a zest for life than I ever realized. Do you have a way that I can completely put it out of its misery without removing it or getting scads of suckers in my yard? (e-mail reference)
A: The key is killing the roots. By girdling the tree, you cut off any source of food the roots might have had from the top. Unfortunately, you also signaled that the top was dead and they should send up some suckers. My guess is that suckers will arrive in full force in a few weeks. All is not lost however. You're going to have to go with some chemicals here. There are a couple that should work pretty well, including Roundup or maybe some others. Check with your local garden shop to see what they have. You can get this to the root system by either spraying the new suckers when they come up or by painting the chemical into the girdle. Hopefully the tree isn't quite dead at the girdle yet, because you still need part of the vascular system to be alive to translocate the chemical to the roots. Be careful to avoid spray drift. (JZ)
Q: Can you tell me the name of a supplier for an Indian summer crab apple tree? (e-mail reference)
A: One wholesaler is Bailey Nurseries in St. Paul. They can be reached at (800) 829-8898 or via e-mail at firstname.lastname@example.org. Their Web site is www.baileynurseries.com. They can give you a list of retailers that they supply in your area. Another wholesaler to check with is J. Frank Schmidt and Sons at (800) 825-8202. Their Web site is http://www.jfschmidt.com. Good luck with your trees! (JZ)
Q: I need some advice on how to properly prune crabapple and regular apple trees. I ordered some trees from a nursery catalog and the trees I received came with quite a few branches. Should I remove most of the branches so there are only three or four left? Should I remove bigger branches that are closer to the ground in favor of the smaller ones up higher? The trees are roughly four to five feet tall. (e-mail reference)
A: In the old days, we used to recommend pruning trees at the time of transplanting, but we've found out that doing so can cause more harm than good. The leaves that will come out this year and be displayed on those current branches are vital to the tree as it establishes itself in the new site. I would hold off on pruning for one to three years until the trees really get established. When you do get to the structural pruning, it's important to keep a few things in mind. Never prune more than a quarter of the branches at any one time. The tree needs those leaves to harvest sunlight and convert it to food energy. If the tree loses too many leaves at one time, it will take a long time to recover. Wide branch angles are preferred, at least 30 degrees away from the (vertical) main stem. It would be even better if they were between 45 and 60 degrees. Keep the main structural branches spaced about 18 to 24 inches apart along the main stem. If you want some more information on pruning, NDSU has an excellent publication online at: http://www.ext.nodak.edu/extpubs/plantsci/trees/h1036w.htm. (JZ)
Q: Are crab apple trees toxic to horses? (e-mail reference)
A: There have been no reported toxicities. Trees sprayed with pesticides would make them toxic.
Q: I have a flowering crab that has very few leaves. The leaves are also very small. The rest of my crab trees are doing fine. (E-mail reference)
A: It sounds like a progressive root rot disease. It is a common disease that can afflict a wide range of woody plants. It is known as armillaria mellea or simply armillaria root rot. From a plant pathology standpoint, this is an interesting disease. It is a soil-inhabiting saprophyte that spreads through vegetative mycelium. The mycelium often remains suppressed in healthy trees but can become active in trees stressed by environmental conditions such as drought, heat stress, compaction or insect infestations. The fungus actually kills the tree by girdling the crown or lower trunk and then colonizes the dead wood as a saprophyte. It can spread to healthy adjacent trees via rhizomorphs (root-like growth) or from root contact. The likely scenario with your tree is that it will continue to decline. The disease will exhaust the carbohydrates stored in the stems and trunk above the girdling fungus until the tissue is completely dead. I suggest that you remove the plant totally, including the root system. Do not replant in the same spot for a couple of years. Sorry for the bad news, but you have lots of company. I lost an apple tree a few years ago to the same disease.
Q: Is there a crab apple tree that does not bear fruit? I have a friend that says she has one in her yard, but does not know what kind it is or where it came from. (E-mail reference)
A: The only tree on the market that I know of is the spring snow crabapple. It should be available in most quality garden center outlets.
Q: My godmother had a crab apple that was red inside and made great applesauce. The tree blew down several years ago and no one knows what variety it was. Any ideas and, if so, where could I get one? (E-mail reference)
A: It’s probably the same one that my wife uses to make red applesauce, the Dolgo. It should be available on the market. Inquire at your local nurseries.
Q: I am interested in growing apple trees, especially crab apple, from wild specimens found around town. I have read "Home Propagation Techniques," but I am still not clear as to what to do. The paper suggests root cutting of apple trees. Can I excavate around some of these apple trees to uncover roots, then cut these roots off, transplant in a suitable medium and expect growth to occur? (E-mail reference)
A: Depending on the species of wild crabapple, yes, shoots may develop on juvenile roots. They can also be formed on the older roots by simply nicking them to see what kind of growth response takes place. In some cases, callus tissue develops, followed by a shoot emerging from the callus. Eventually new roots develop at the base of the sucker growth. After that happens the developing plant can be removed from the parent stock. If you are going to go the root-cutting route, you want to use a plant growth regulator (PGR) to aid in shoot development. To get buds to develop, you need a PGR that is high in cytokinnins and low in auxins. This will help stimulate new root formation and stem bud development. If the trees are going to be sacrificed, simply cutting them down this spring before new growth emerges will produce a plethora of new sucker growth from the root system, which would give you plenty of stock to select from. This assumes that the plant stock you are referring to is healthy and showing a moderate amount of vigor.
Q: My mother gave me a tiny crabapple tree she received from the Arbor Day Foundation. I have no idea what kind it is. I planted it on a partially shaded side of the house. It has been there for three or four years and seems to be growing just fine, but it has never bloomed. Does it need more sun? Could I move it without killing it? When is the best time to move it? (E-mail reference)
A: You could move it, but I wouldn't recommend it. Sometimes it takes crabapple and other fruit-bearing trees five or more years to mature enough to flower and fruit. As long as it gets about six hours of direct sun each day that should be sufficient to get it to bloom eventually. Don't make the mistake of fertilizing with turf fertilizer around the tree. This highly nitrogenous fertilizer material is good for the turfgrass and will cause the tree to put on lots of vegetative growth, but it does so at the expense of flowering, and sometimes disease resistance. If you are locked in to moving it, then do it this spring before new growth emerges with as large a root ball as you can handle and be sure to set it at the same depth.
Q: I would like your recommendation about a crab apple tree that we hope to plant near our house. I have a spot that is approximately 20 feet by 20 feet with the property line fence on the north side, my house on the east, a deck attached to another portion of my house on the south, and part of the same deck (L shaped) on the west. We would like something that has a shape that would fit into the area and not over-power the house. We would like something that has nice flowers, holds its fruit to avoid a constant mess, has small red fruit and preferably red leaves as they age towards fall. I would appreciate any advice you could give us on what would be hardy for our area and come close to what we would like in that type of tree. (Grand Forks, N.D.)
A: The one that comes to mind is the thunderchild crab. It gets 12 to 20 feet tall, has nice pink flowers, deep purple leaves and small, persistent fruit.
Q: I have an ornamental crabapple that I planted a few weeks ago. I have noticed that the leaves are always folded inwards. Could this mean the tree is over or under watered? (E-mail reference)
A: The first thing I would suggest is to look inside the folded leaf and see if there is a critter there. Some insect larvae will make a cocoon that way. It could also be responding to high temperatures as a means of conserving water. Many times the symptoms of over or under watering are exactly the same. That is a determination you will have to make. Most people tend to overwater.
Q: I understand that one should avoid trimming a crab apple in June or July. I have a tree trunk that did not get leaves this year. Should I trim it now or wait until winter? Also, is this dead trunk a sign of things to come for the rest of the tree? (E-mail reference)
A: Try to avoid pruning apples or crabapples in the hot, sticky months of summer to avoid possible disease problems but if the branch is dead, it isn't a good idea to keep it around either. I would recommend cutting it back to just outside the collar. This is not necessarily a sign of things to come. It could be the branch died of a cankerous fungus or borers that may have decided to take up residency in your tree. Monitor the condition of the tree and try to catch any anomalies that may show up early so they don't become a lethal threat to your tree.
Q: Can you tell me how to stop the suckers from growing on my crab apple tree? I cut them off each spring and they keep coming back. (E-mail reference)
A: Visit a local garden center or nursery and ask for "Sucker Stopper." Spray it on after you cut the suckers back. That should take care of them for the growing season.
Q: We have a white flowering crab apple tree. We pruned it last fall and this summer it did not flower. Did we do something wrong? Was it pruned wrong? What is the proper way to prune this tree? When is the best time to prune it? (E-mail reference)
A: You could have pruned off too much. You didn't say whether or not it leafed out, but I assume it did. The best time to prune is early spring before new growth emerges, depending on where you live.
Q: I have a friend who doesn't like all the apples that develop on his crab apple tree. Is there a spray of some kind which will deter the growth of these apples? (E-mail reference)
A: There are none that I could recommend with any degree of confidence. There are sprays that claim to control fruit set but they are variable in performance due to timing and cultivar differences.
Q: I have two crabapple trees in my front yard that are around 20 years old or older. I am having a problem with limbs dying. They have been falling off all year long and one seems to be rotting from the inside. Any ideas? (E-mail reference)
A: It sounds like your trees are not long for this world. You can get someone locally, such as an arborist or county extension agent, to come out and give you a better diagnosis than I can at this distance. You might start looking through some of the spring catalogs that are beginning to arrive to make a replacement selection.
Q: I would like to put a crabapple tree in my front yard. I went to the garden center today but they don't have pictures of what the tree looks like when it’s full grown. I know what I want, so I would like to take a look at pictures of full trees (not just the fruit). Can you recommend a book that would supply me with pictures and information? I want something that’s disease resistant, 15 to 20 feet high, not upright growing and will have small red fruit in the fall through winter (fruit like the winterberry tree). I read about the sugar thyme and it sounds like something I would be interested in, but they didn't show it full grown. I'm an avid gardener but I'm very specific in what I buy. (E-mail reference)
A: There are as many different crabapple types as there are different Smiths! The best bet for you is to contact the local county extension office and see if they have a horticulturist that can help you. Crabapple selection is very a local process and there are literally thousands to select from. The cultivar you mention, sugar thyme, is listed in one of my references. Here are its characteristics:
Flowers: Pale pink buds that open to sugar white fragrant flowers.
Fruit: Red, one-half inch diameter, abundant and persistent.
Habit: Upright oval, vigorous, 15 to 18 feet with crisp dark green foliage.
Diseases: Very resistant, slight scab in Ohio (1997). Test evaluations great in Michigan, Minnesota, North Carolina, South Carolina and Vermont. Good Japanese beetle resistance but poor fireblight resistance. Hope this helps!
Q: I have a flowering crap apple tree that is about two years old. I will be moving soon and would like to take it with me. Is it possible to dig up the tree in October and transplant it somewhere else or will I have to just leave it for the new owners. The tree is pretty small right now. (E-mail reference)
A: Any tree would be better off at the same location rather than digging it up. But it can be done, especially at the stage of life it is at right now. Just make sure that the new owners didn't consider it part of the purchase price of the property.
Q: Do you have any experience with tree propagation? I've been trying to propagate my root shoots from a miniature crab apple tree but they won't take. I use Roottone and sandy soil. They grow like crazy from the ground around the base of the trees but won't start on their own. Any suggestions? (E-mail reference)
A: Try the process of "stooling" where the soil is mounded up over the shoots after they are wounded at the base. I'll forward you my publication of "Home Propagation Techniques" where that technique and other propagation processes are explained.
Q: I have a crab apple tree that the wind blew down this year. I cut the tree off at the ground. Now I have about 50 sprouts coming up in my yard where the tree was. Can I dig these up and plant them somewhere else? If so, when would be best time to do this? (E-mail reference)
A: The chance of success with transplanting sprouts is limited due to the fact that you are removing it from a big reservoir of stored nutrients from the inter-connecting roots. If you dig out a sprout, all you will take is about 10-12 inches of fleshy root with you which has limited ability at picking up water and nutrients. That said, why not give it a try? Do the digging in the early spring when they are still dormant. Water and fertilize well. The sprouts will leaf out initially, but then it will be interesting to see if you get any new growth beyond that. If they do, then you have likely succeeded, and should be congratulated!
Q: Could you tell me if it is OK to cut the suckers from my crab apple now, in June? (E-mail reference)
A: No problem, go for it.
Q: I have a crabapple tree that has a ton of fruit on it. The problem is we don't use the fruit. Is there a spray that you can use to keep the tree from bearing fruit? If not, is there any other method short of cutting it down, which is what we will have to do if there is nothing we can do to control it. (Grafton, N.D.)
A: There are sprays, but they are not dependable. I have a Dolgo crabapple that bears way more fruit than we can ever get to, creating a mess that I have grown to hate cleaning up in the fall. My solution is going to be to cut it down after flowering this year and replace it with something that is not as messy.
Q: I am looking to purchase two crab apple trees for my mother this spring. She repeatedly tells me that Snowdrift crab apples make the best jellys and jams. However, as I've been researching them, many places tell me that Snowdrift crab apples are only for animal consumption. I was wondering if you could recommend different crab apple trees that would survive this weather, as well as taste great as jam. (Detroit Lakes, Minn.)
A: Listen to your mother. She is probably right! As far as which crabapples make the best jelly, I cannot say, but we have had excellent jelly from Dolgo, Centennial, and Chestnut. I suspect that the low quality rating of some of the crabapple fruit is due to the small size of the pomes, making them difficult if not impossible to convert easily into jelly.
Q: I have a 25 year old ornamental crabapple that has gotten too big. I have tried pruning branches back to thin and reduce its height, but new branches sprout densely and grow very long during the next summer. I understand there is a hormonal balance between roots and shoots, so I spaded around the tree about 6 feet from the trunk, 8 to 9 inches deep, to cut roots. Still the branches sprouted. How can I get the tree reduced in size without it becoming dense with new, long growth? When should this be done? (Jamestown, N.D.)
A: There is a basic rule of thumb: to stimulate growth, prune when dormant; to slow or reduce growth, prune after leaf out. The idea behind this is that by pruning in late spring or early summer, photosynthizing material is removed, which reduces the vigor of the tree. Doing it just once will not do the trick. It must be done annually and sometimes twice during the season. The bad news about this is that pruning in summer or when the trees are actively growing opens them to disease spore invasion. Consequently, I would advise carefully selecting the time to do such pruning when there is no rain or high humidity and high temperatures forecast for a few days. Once these plants mature, and if they are healthy, their growth can be difficult to control, so don't give up.
Q: My mother in law has some type of flowering crab that has lost most of its leaves. The remaining leaves look like they are drying up. The fruit looks perfect, but seems a little small. I've looked up apple scab and it doesn't look like the pictures. It's planted in very sandy soil. We don't like using chemicals. Any suggestions? (E-mail reference)
A: With no chemicals being used, you are then limiting yourself to very few choices: Put up with what is happening and hope that the weather improves over the years so that the disease doesn't manifest itself to such an extent. You can help lessen the impact of the disease by cleaning up all fallen leaves in the autumn. Spraying with lime-sulfur (approved for organic use) will help to sanitize the tree when dormant but is not listed as a control for the disease. Or, remove the present tree and replace with a more resistant cultivar, which depends on where you live.
Q: What are the chances that my 'Donald Wyman' crab trees are grafted/not grafted? I lost quite a few this past winter, and want to know if I can choose a nice sucker from the many that are sprouting and cut out the little dead tree. I don't want any crab but Donald Wyman. I do not see signs of a graft, but I am not all that proficient, I'm afraid. (E-mail reference)
A: Not very likely, unless someone before you happened to root a cutting and plant it successfully at that location. Just about every named crabapple that I know of is a clone of the parent, which means that it was vegetatively propagated (grafted, budded, or by cuttings) from the parent tree. It is unusual to hear of a survival problem with this named cultivar, an introduction from the Arnold Arboretum which is in the Boston area. There is also a slight chance that the graft was buried at planting, and some of the sprouts that are arising from the base could be above the graft union and would therefore still be the 'Donald Wyman' crab.
Q: I have several crab apple trees, all are about 40 years old. They continue to bloom every other year but need to be trimmed. What is the best time of the year to trim. (E-mail reference)
A: The best time to trim is in the early spring, when the trees are still dormant. Trimming now would predispose the trees to disease entry, especially fireblight, so it is not recommended during the summer weeks unless necessary to prevent breakage or to correct a hazardous situation.
Q: I have two Japanese crabapple trees that I bought two years ago as very small trees, Now they are about 9 feet tall but this year had no blooms on either of them. Do I need to fertilize them or prune them to get them to bloom? I am very new to this and want them to bloom next year. (E-mail reference, Sacramento, Cal.)
A: Not needed. The lack of blooming is more likely related to weather conditions than it is to fertilization or pruning. I would suggest contacting your local extension horticulturist at UC and asking for a publication on care of crabapples in your region.
Q: We have two large flowering crabapple trees that canopy our back yard. They are very beautiful with vibrant pink blossoms. Each year they seem to get very large cocoons of caterpillars on the ends on the branches. What are they? and how can we get rid of them? Are they destroying our trees? (E-mail reference)
A: Those are tent caterpillars, and they love fruit trees! While they are unsightly and can be locally destructive, they seldom cause sufficient damage to be worried about. If you can, cut off the ends of the branches they are on and burn them. Next spring, spray the tree with dormant oil while it is still dormant, and the oil will kill the overwintering eggs.
Q: I have four Spring Snow crabapple trees (about 8 to 10 years old) planted in a line about 10 feet apart in a flower bed. Three of the trees have always been good with flowers and leaves. One tree (a middle tree) is not growing as vigorously, and although it blooms, it gets very few leaves in the summer. It has been doing this for about four years. What should I check for to determine why this tree is not thriving like the others? The trees are intermixed with burning bush, which is doing fine as well. (E-mail reference)
A: It sounds like it could be a canker, root rot or borer problem. My first suspicion is canker. Look for a darkening or ring around the affected branches. Cankers (dead tissue) are often caused by fungal organisms and gradually girdle the branch, killing it completely. In the meantime, the vigor of the tree declines as yours is doing. Having said that, it is unusual for a crabapple tree to be afflicted with such a disease. Another possibility is root rot. If you can, dig down around the base of the tree and see if you can find any decay. In either case, there is not much one can do. If the tree doesn't pull out of this funk this year, then I suggest replacing it ASAP to keep the disparity between the established trees and the new planting from being too great. Borers attack mostly stressed trees starting with small branches. If branch tips seem to be dying back, follow the dead parts back to see if you can find small holes in the stems. If you do, then remove it and slice into the stem around the hole. You will find galleys where the borer has fed and likely girdled the branch, killing it. They are difficult to control once they get started, and I would rather see you replace the tree than to put a lot of pesticide into the environment attempting to control them.
Q: I am concerned about a flowering crab that we planted in the summer of 2000. I'm not sure how old it is, but it is a very young tree, only about 6 feet high with just a few branches on it yet. At the end of February, a friend of ours was snow machining on our property, which is adjacent to the bush. He thought that the "stick" poking through the snow was just a scrub tree, and ran over it twice with his machine. Although the tree was bent right over against the snow, it didn't break and is still standing straight and tall. My concern is that the snow machine rubbed off some bark in several places. The reddish outer layer is gone and I can see green wood where the scuffing occurred. What do I need to do to protect the trunk and keep out any disease or insect infestation? (E-mail reference, Atikokan, Ontario, Canada)
A: Actually very little. No covering should be placed, nor any sealer placed over the wounds. I would suggest keeping them open, but "clean them up" by cutting away any torn bark, back to where it is attached, with a sharp knife. Encourage vigorous growth of the tree this spring, with adequate water and nutrients - not excessive - and the bark will begin healing over the wound. The tree actually "compartmentalizes" the wound to keep it from becoming contaminated with decay organisms, so the role of the gardener is to facilitate that action. Covering it or sealing it only inhibits what we want the tree to do. Put a big flag or fence around the tree next winter!
Q: Do flowering crab trees have a life cycle or age limit? We are fighting leaf spot and/or apple scab on a very large tree, about 20 feet tall. I'm going to buy better fungicide delivery equipment but only if there is a chance to save it. The tree is about 23 years old. (E-mail reference)
A: There is a probability that you can save it, but if it is prone to apple scab or other diseases, it will be an annual fight, and one that usually get worse as time passes. You are better off having the tree removed and replacing it with one that has resistance bred into it.
Q: Can you tell me what is causing the leaves on my flowering crab to turn brown and fall off? Someone told me it might be fireblight, but I am not sure. (Devils Lake, N.D.)
A: Your apple may indeed have had fireblight, but it also has some type of leaf spot fungus. Which one, I cannot be sure without a lab test. Basically, you should clean up all fallen leaves and fruit this fall. Spray next spring with lime-sulfur before leaves come out, and follow up with Captan or benomyl.
Q: We have two ornamental crab apple trees in our backyard which have been losing their leaves all summer and are now almost bare. What is the problem and how do we treat it? We would hate to lose these trees! (Milbank, S.D.)
A: Your tree has apple scab--Ventura inequalis--which is brought by rainy, humid weather and host susceptibility.
First, clean up all fallen leaves and fruit this fall. Then, next spring before leaf-out, spray with lime-sulfur. After leaf-out, begin a program of spraying with Benomyl or Captan on a 10- to 14-day cycle during vulnerable periods--wet, humid weather.
If all of this is too much, then simply replace the tree with a resistant cultivar. There are plenty to choose from.
Q: Can you tell me why the leaves on my crab apple trees have a wilted and blotchy appearance? I began using a fungicide for leaf scab at seven-to-10-day intervals, but I think I may have been too late. When is a good time to spray them and should I use a fertilizer this fall? I heard that fertilizing apple trees can promote rapid growth and fireblight. Is that true? (Fargo, N.D.)
A: Fungicidal sprays should be applied as the leaves open. You can use chlorothalonil, which is probably the best selection. I find that using lime-sulfur as a dormant spray prior to leaf-out can also aid. You are right--fertilizer can cause excess growth and can lead to fireblight.
Q: Can you tell me how to control quackgrass in my iris bed? I also would like to know if there is anything I can spray on my crabapple tree to prevent suckering? (e-mail)
A: Quack in iris beds is a tough one to get under control. Poast can be used, but I am finding out it is difficult to find. The only other option is dig the bed up and remove the quack by hand.
No, there is nothing you can spray on the roots of the crabapple to prevent suckering. You might try cutting the suckers off with a weed cutter that goes below the soil surface and raising the mower height to 3 inches if it isn't already there. Sometimes that procedure will at least reduce the number of suckers that have to be dealt with!
Q: I have two ornamental crab trees in the back yard. In the fall when the apples fall it creates a mess and nearly kills the grass. Is there a spray that can be applied to prevent the apples from forming? If so, what is it and when and how should it be applied? (New Rockford, N.D., e-mail)
A: There might be sprays on the market that purport to eliminate apples, but I have not tested any and cannot vouch for their effectiveness.
The common insecticide, Sevin, is often used with success. A lot depends on the timing of the spray and the cultivar of the tree.
Make the application at about three-fourths full bloom, and about five to seven days later. Do the spraying in the early morning hours when the bee activity will hopefully be nil and the wind calm.
No guarantees on results! Good luck!
Q: Can you tell me why my crabapple tree appears to be dying? (York, N.D.)
A: The tree is showing symptoms of apple scab, an especially bad fungal disease this year because of the humid, rainy weather we experienced at the start of the season.
This can be controlled with one of the broad-spectrum fungicides in the spring when the buds are showing green at the tip, then again after full leaf expansion. Materials like Captan, Ferbam, or Mancozeb will do the task.
Q: Can you tell me whether the enclosed berries are edible? (New Rockford, N.D.)
A: Your tree is a crabapple, and the fruit makes excellent jellies and applesauce
Q: For the last two years, my crabapples have had this scab on them. What can we do to prevent this? (Wilton, N.D.)
A: The scabby fruit is still edible, just not as attractive. Go ahead and make apple sauce with it and enjoy!
Next year at petal drop, spray with a fungicide like Captan or Chlorothalonil. Repeat in 10 to 14 days. If only one or two branches are covered with tent caterpillars, prune them out and burn.
Monitor the tree next year and if you should see an infestation getting started, spray with the bacterial insecticide Bt (Bacillus thuringiensis)
Q: Enclosed are some leaves off a Radiant crab tree I planted about a year ago. I did not have this `blight' on it last year, and now it seems to be spreading to other trees. Help! (New Rockford, N.D.)
A: Your apple tree has a good dose of apple scab. Spray with Captan to prevent further spread of this fungus.
This fall, be sure to clean up all fallen leaves and apples. Next spring as leaves open spray again with Captan.
Q: I am enclosing leaves from a flowering crab tree. It seems to be sick. (Wimbledon, N.D.)
A: Your crabapple has a very bad case of apple scab (Venturia inaequalis). It is turning out to be a very prolific disease this year due to our wet weather.
Spray the tree immediately with Captan. Then, most importantly, clean up all fallen leaf litter this autumn—or in early spring before seasonal leaf-out occurs. I would also recommend a spray with lime-sulfur at that time, before leaf opening.
Once the leaves open, begin a vigorous program of preventative sprays with Captan or Captan plus benomyl. Continue every 10 days as long as the weather is conducive to disease development.
Q. Awhile ago I read somewhere that you could put something around the base of crabapple trees in the fall and they wouldn't flower or bear fruit the next spring and summer. I have misplaced the article so am wondering if you have any advice for me. I was told to spray the blooms in the spring with Sevin, but I don't care to use that method if there is another that will work. I am afraid of the spray business. (Wishek, N.D.)
A. I am afraid that is the only choice, unless someone knows something I don't, which is always possible (and even probable).
Properly handled, Sevin or any other pesticide will not create problems.
Q. What kind of crabapples are these? They are loaded and make good jelly. (Nome, N.D.)
A. Your tree is a Dolgo crab. Mine is equally loaded and it makes good applesauce as well.
Q: I have been reading your Web page in order to find a tree that would do well in our area--Denver. The local tree farm recommends the Spring Snow Crabapple, but after reading your information on crabapple trees, I am not sure if it is disease tolerant. Would you recommend this tree for our climate? I would like to obtain a tree which is not disease prone, does not need too much water, and grows in kind of an oval shape. Other choices I have looked at are the Canada Red Cherry and the Newport Plum, but they too seem to be prone to disease. (Denver, Colo., e-mail)
A: Spring Snow crabapple is rated in our trials as having good disease resistance. It bears no fruit and is oval to round in shape. Other highly recommended crabapples that you may want to consider are the following: Centurian, Donald Wyman, Indian Magic, Indian Summer, Prairiefire, Red Splendor and Thunderchild. All are fruit bearing, and all are rated as excellent to good with respect to disease resistance. Our trials are carried on all across North Dakota. I don't know of any reason why they shouldn't do as well in your area of Colorado.
Q: An idea I've heard about driving nails into apple trees to stimulate them to bear fruit is very interesting. How do you do it and how does it work? Can coffee be used to stimulate any plant, or just certain types? Do you dilute the coffee, or use it full strength? Are coffee grounds good to put around plants in a flower bed? Are there any colored flower varieties of crabapples that are fruitless, or just the couple white varieties? (e-mail)
A: Yes, driving nails into trees may stimulate them to bear fruit, but it is also quite injurious to the tree, so I don't really advise it. Girdling branches also does the same thing, but then the branch dies! A less traumatic practice would be the take a square-tip spade and drive it into the soil out around the drip-line of the tree (the outer edge of the canopy) to sever some of the roots. This usually makes a pretty clean cut, which heals faster, and often results in the tree bearing fruit the following season. Coffee is a complex compound, in addition to caffeine, coffee contains nearly 400 other chemicals, including trace amounts of vitamins and minerals, tannins and caramelized sugar. It has an acidifying effect on the soil, and the used grounds tend to enhance the tilth of the soil. I have known many people, and perhaps you have too, who say all they have done for so many years is dump their old coffee on their house plants. I don't know of a plant that would be harmed by coffee. The only crabapple I know of is Spring Snow, which is white.
Q: Are all the fruits on flowering crabapple trees edible? We have one that produces dark pink blossoms in the spring and this year it is loaded with small dark red to purple apples. Are these edible? (E-mail reference)
A: All fruits on crabapples are edible - some more than others - depending on the size and how juicy they are. Just be sure they have not been sprayed with a pesticide.
Q: I have a flowering crab apple tree that is 12 to 15 years old. Over the years it’s had the typical problems, such as gypsy moth, tent caterpillar and leaf fall off through the summer. I've sprayed it with Sevin, which seemed to work at the time. This year I've noticed a green scale or flaky material on the trunk and lower branches and the bark is now peeling off. What's the problem and how can I deal with it? (E-mail reference, Lewistown, P.A.)
A: It sounds like your current concern is nothing to worry about. That is either moss, lichen, or algae forming on the lower, east, or north sides of the tree. Bark exfoliation is also somewhat normal at that age, with the older parts of the tree. It often occurs after a period of rainy weather that was preceded by an extensive dry period. I'd suggest spraying the tree next spring with a dormant spray lime-sulfur next spring before the leaves emerge, then spray with Bordeaux after the blossoms have fallen, and again about 10-14 days later. That should keep your tree somewhat healthier than it sounds like it has been.
Q: We had a crabapple tree that we dug out last spring. We dug down approx. 4 feet to get as many roots as possible. We are experiencing little suckers that are sprouting up as far away as 20 feet from where the tree base was. We are using Roundup on each individual little varmint that sprouts. Is there a secret way to eliminate these sprouts without having to continually address each individually? (E-mail reference, Glenrock, Wyo.)
A: The answer is simple. Use a broadleaf herbicide like Trimec and apply it like you are trying to control dandelions, plantain, or similar weeds (everybody's lawn has them!). You will incidentally kill off those suckers that are coming up from the old root system without hurting the grass.
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