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Hortiscope

Ron Smith answers questions about flowers, trees, gardens and shrubs.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: We have been told that what we thought were weeds in our front lawn are suckers from the roots of white birch trees. We recently removed a damaged birch tree close to this area. Is there any way to know if the suckers are from the removed tree or if we may have damaged another one? Is there any way to control the spread of the suckers without damaging the trees? Your help would be greatly appreciated. (Brimfield, Md.)

A: It is unusual for birch trees to be sending up suckers, so what you probably have is the residual from the removed tree sending up the sucker growth. Light applications of a broadleaf weed killer used on lawns should kill them without harming the living birch tree's roots. Any herbicide that is available in retail stores labeled for selective control of broadleaf weeds will do the job.

Q: We bought a house last year that has three tall white birch trees. The trees appear to be very healthy and happy because we have catkins everywhere. Starting last fall, I noticed a birch seedling coming up in a different part of my yard and have let it continue to grow because I love these trees. I have been trimming the lower branches to encourage it to grow taller and want to know if I am doing the right thing. At what point or height should I stop trimming and let it do its thing? At what age can I transplant the tree with the least stress? Is it possible to train this sapling to weep? (San Jose, Calif.)

A: The younger it is, the easier it will be on the tree and the mover. I would suggest waiting until late fall or early winter to do the moving. As for trimming, I have a rule of thumb with my birch trees that says any branch that interferes with my mowing gets trimmed. The longer you leave branches on the tree, the faster the trunk will thicken. Give it another year before allowing it to "do its own thing." If it is going to weep, it will do so on its own, so all your clever maneuvering with pruning won't achieve that weeping effect. Sorry.

Q: I was reading some of the material on your Web site hoping to find the answer to a problem we noticed this spring. I have a fairly young semidwarf yellow delicious apple tree that has absolutely no blossoms on it this year. We did have a nice crop of apples last year and don't understand what might be wrong. The leaves are growing, so it's not dead. We also have a granny Smith planted within 30 feet that's in full bloom. Your help is appreciated. (Connecticut)

A: What you describe is unusual, but it does happen. Flower buds are more sensitive to low temperatures than the foliage buds are, so that could have caused the problem. Another possibility is that this tree is particularly prone to alternate-bearing. If the crop was heavier than usual last year, it could easily result in it not bearing this year. Glad your granny Smith is producing so well because they are great tasting apples! The other one should bear fruit for you next year. Just don't do anything drastic to it this year.

Q: My gerbera daisies started out beautifully with lots of gorgeous blooms. However, there are no more blooms shooting up. The green of the plants is lush and very healthy. Any idea on what to do to get more blooms? I do deadhead when the blooms are spent. (DeKalb, Ill.)

A: You have done everything you needed to do, so be patient! They will bloom when they are good and ready!

Q: My grapevine is finally producing fruit, but now I have discovered that Japanese beetles love the leaves. My husband has sprayed with Sevin. However, I have found that a few of the leaves have little, furry growths on the backs of the leaves. This may be impossible for you to diagnose, but I am grasping for help. Our Extension Service people have moved from the area, so now I don't know who to show this problem to for assistance. Thank you for any help you may be able to give me. (e-mail reference)

A: This could be rust spores developing. See if you can locate a Bordeaux mixture on the local market to use to keep this fungus from spreading.

Q: I have had my jade indoors for about five years. A week ago, I moved it outside to a shady spot under a pine tree. We have had very hot and humid weather this week, but also some rain. The plant now has very red stems and the leaves at the tips are getting soft. Any suggestions? (e-mail reference)

A: I would say that you have nothing to worry about. The plant is responding to the change in environment. Keep in mind that the genetic hardwiring of this plant is in the tropical regions of South Africa, so it shouldn't buckle under any hot temperatures in North America. Just don't allow the plant to dry completely, but also don't overwater it. Remember that jade is a succulent.

Q: I planted a live oak tree two weeks ago. It was looking good until we had a rainstorm and now the leaves are turning brown. What do I do now? (e-mail reference)

A: Check to be sure the roots aren’t standing in water. If so, dig spoke trenches to get the water to drain away from the roots. Check to be sure that it isn't planted too deeply. If it is, then pull the excess soil/mulch away from the tree until you reach the crown, which is the point where the trunk becomes the root system. If it is neither of these problems, then all I can suspect is a lateral movement of some herbicide into the root system that is killing the tree.

Q: We planted three apple trees three years ago. They are growing nicely and blossomed for the first time this spring. During the last couple of weeks, I have noticed that one of them has leaves that are turning yellow and falling off. There are a few little apples on the tree, but they are very small and some look deformed. Is there something we should be doing to the tree? We did not fertilize this spring. Should we apply some kind of fertilizer? If so, what should we use? (e-mail reference)

A: If they have grown in the past couple of years without these symptoms, then my guess is that something has changed around the environment of that tree. Were any herbicides applied around the tree? Were insecticides or fungicides sprayed in the area? Is that tree located in an area that has poor drainage? Was it planted deeper than the other two? These are just some of the conditions that would result in the symptoms you describe. Applying fertilizer rarely is needed in most backyard fruit tree plantings and will not correct anything other than a nutrient deficiency, which doesn't fit the pattern you describe.

Q: We have an arbor that we would like to grow grapes on, but my daughter only likes green grapes. Is there a variety of green grape that would be suited for this purpose and this region? Also, I would like to know about a raspberry bush I could grow in this area. (Jamestown, N.D.)

A: The only one I know of that has a chance of growing in Jamestown is the edelweiss because it was produced in Minnesota. A couple of good raspberries would be latham, which ripens in early summer, and Redwing, which is a fall-ripening variety.

Q: I have a braeburn apple tree that I planted from root stock 15 months ago. At first, everything was going fine with new growth and leaves. Again, as spring came around this year, more growth and leaves. After awhile, the new leaves began to look as if they were blistering. They would turn brown, then darker and eventually curl up and drop off. This is happening every time there is new leaf growth. Am I doing something wrong? It is watered well, has good top soil and had a good soaking of liquid seaweed feed prior to planting. (Nottingham, England)

A: This could be symptomatic of overwatering, which keeps the roots too wet or there is a salt buildup in the soil. My inclination is to think it is from too much water. In America, a neophyte gardener tends to plant too deeply. The tree's crown, which is where the stem transits to become the root system, should be at ground level and not any deeper. Some people get that right, but then bury the roots in too much mulch made of stone or bark. Check these factors out to make sure you are not in any of these situations. You might want to tap into your country's equivalent of our Extension Service, which is the Agricultural Development Advisory Service. You can find it at http://www.adas.co.uk/. Perhaps a horticulturist with the ADAS can assist you better than I can with your problem. All the best and thanks for making contact.

Q: I have a 5-year-old autumn blaze maple. It was a 12- to 14-foot tree I purchased from a nursery and came in a pot. The tree appears to be growing and healthy. However, the leaves are very yellowish green. Any ideas as to what is wrong? (e-mail reference)

A: If the tree has been in its present site for that long, then it is suffering from either iron chlorosis or nitrogen deficiency. You can try correcting it with applications of an iron-based fertilizer, such as one containing iron sulfate or any other iron-containing fertilizer available on the local market. The nitrogen needs of the tree should be met with normal lawn fertilization. Ignoring this will lead to the eventual premature death of the tree, so work on getting it corrected at your earliest convenience.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu.


NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161, ronald.smith@ndsu.edu
Editor:Rich Mattern, (701) 231-6136, richard.mattern@ndsu.edu
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