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Ron Smith answers reader's questions about the world of plants and gardening.

By Ronald C. Smith, Horticulturist

NDSU Extension Service

Q: Hi! It's been a long time since I've contacted you. You helped me get started with my pumpkin "farm." As you may recall, I have been giving all of my earnings to build churches in India. I'm happy to report that 11 have been built. It is great fun and I enjoy it more every year. Here's my question. I have two plots that I rotate for my pumpkins. Last year my husband rigged up an irrigation system from the nearby slough that sprays water on almost all of one plot. The other plot doesn't have irrigation. I know you shouldn't plant on the same ground two years in a row, but since one plot doesn't have irrigation, I'm tempted. What do you think I should do? (e-mail reference)

A: Congratulations on such a major accomplishment just from selling pumpkins. Pumpkins have been grown for many decades without supplemental irrigation. You will get better production from irrigated plantings, so set your expectations a little lower on the nonirrigated plot.

Q: I have a lilac tree that always has been purple. Last year I noticed it was all purple, but had two white flowers. Now the entire tree is covered with white flowers. What happened? How can I change it to a deeper, darker purple? (e-mail reference)

A: No idea. All I can guess is that the purple scion wood flowers were grafted onto white rootstock. Sorry. If anybody comes up with an answer, I'll let you and everyone else know!

Q: We have a blue spruce that my children planted about 18 years ago. We moved two years ago and brought it with us. It was doing great, but the tree got hit with salt from the water softener because of a problem. As soon as we saw this, we fixed the softener, but the tree is almost completely brown. We are watering periodically to flush the roots. Please help! (e-mail reference)

A: Check to see if the buds are green under the scales. If they are, there is a chance the tree will come out of this. If they are brown and dry, don't waste your time and consider the tree dead.

Q: I was about to plunk down hard-earned cash for a dogwood fertilizing kit when I spied your Web site. We live in Virginia on a dogwood-lined street. We planted five in front of the house two years ago. One is at the drip edge of a linden tree. Its leaves are sparser than the others. Is it stressed for water or in need of fertilizing? Is it doomed? Thank you for your advice. (e-mail reference)

A: Dogwoods are subcanopy trees that thrive along the edges of wooded lots or forest stands. The linden is a very densely leafed tree when it has a full canopy, so it might be that the tree is casting solid shade. Dogwoods do best in dappled shade or full sun. I believe that the problem probably is water and nutrient competition from the linden or the roots are exuding an allelopathic substance that is inhibiting the growth of the dogwood. I would try some extra fertilizer and water to see if the tree can be knocked out of this funk. Otherwise, I don't know what else to suggest.

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: I just discovered your Web site and was wondering if you can answer a few questions. Where can I get Juneberry plants? Is it easy to transplant them? If I were to go where they grow wild and try to transplant them to my backyard, would it work? Thanks for any help you can give me. (e-mail reference)

A: Most garden centers carry Juneberry plants. They can be dug from the wild, but it needs to be done while they are dormant, such as early spring, for maximum success.

Q: I have a spider plant that I received as a gift. I live in Michigan and this was during the worst part of our winter. After a short car ride to my dorm, I brought the plant inside. Shortly after, all of its leaves began to die. A friend of mine fed it some plant food and the plant grew new leaves and rebounded. While I was away on spring break, my parents left my spider plant out and my cats ate most of its leaves. Once again the plant rebounded, although you can still see the places where the cats ate it. A couple of months ago, I transplanted it into a bigger pot. I used new potting soil. The plant has been doing well in this new pot. I moved home from college for the summer.

Since then my plant has not been doing as well. One day I watered it and took it outside to bask in the summer sun. A few hours later, I noticed that two of the longest leaves were wilting at the ends. I brought the plant inside thinking it was too hot, but the plant hasn't perked up even though it has been almost a week. The affected leaves are limp, losing color and turning brown. I water it with filtered water from our tap. Should I get distilled water? Could I be watering it too frequently? I gave the plant a small amount of diluted Miracle-Gro two days ago thinking that might help. I am quite attached to this plant. I even named my plant Charlotte. (e-mail reference)

A: Your "Charlotte" has lived a pretty full four months! These are tough plants and can tolerate abuse from cats and underwatering. I need to emphasize that this plant can take some generous watering, but it does not like to have a soggy soil medium surrounding the roots. If the pot is not free-draining, then that is the problem and you need to change it right away. It has the potential to make a comeback with the right remedial care. If not, get another one and learn from your past mistakes!

Q: I live in the northern part of Ontario. We purchased 70 emerald green arborvitaes and planted them this past weekend. Because of where we live, I would like to know if I should wrap them with burlap this winter. Also, should I use an anti-desiccant spray for foliage so they remain green? I am using the arborvitae as a hedge for privacy. Our winters here can go to minus 40 in the winter. (Timmins, Ontario)

A: Wrap them in burlap, but avoid using any anti-desiccants. We have had mixed results with the material. With a planting this large, I would hate to see you lose all of them because you used an anti-desiccant. Be sure they go into winter well hydrated. Don't fertilize because this will cause soft, lush growth that looks beautiful, but is vulnerable to winter burn. After about three winters, you should not need to continue with the wrapping. Your winters are no worse than ours here in North Dakota!

Q: I met you a few days ago at a gardening event in Hope. I have a question about strawberries. A lady called me and mentioned that she found deformed strawberries (knoblike fruits) in her garden last year. All the seeds seem to clump in a small area of the deformed fruits. Is this caused by an insect? I do not have any pictures or samples of the deformed fruits, but the lady wants to know the cause of the deformation and how to deal with it. I have a copy of publication E-299, but it does not describe the injury symptoms. Your cooperation is very much needed to solve this problem. Thank you in advance. (e-mail reference)

A: These deformed fruits are called "nubbins." They are formed from a number of sources, such as frost damage to the pistillate part of the flower, lygus bug feeding activity or the lack of bee activity because of cool, windy or wet weather during the time when pollination should be taking place.

Q: I have a pink dogwood in my front yard that has few blossoms. It needs a bit of pruning to remove some dead branches, but nothing major. The leaves look healthy and it has good coverage. Is there anything I can do to increase the blossoms next year? (e-mail reference)

A: The sparse blooms this year could be weather-related and nothing more. Basic care is all that is needed. Dogwoods like acid soil, so look for fertilizers that are meant to acidify the soil.

Q: We have a lot of green ash trees. They are starting to get some size and looking nice. We also have eight to 10 that are smaller in size. After reading about possible contaminated firewood imports, I'm wondering just how long it will be before some such incident introduces the borers here. Maybe it would be a good idea to pull the small ash out and start planting some other species for more diversity. What do you think? We have planted some silver and autumn blaze maples. I also read about the Asian long-horned beetle. What kind of trees would make good replacements? We need something that grows fast because we are in our 60s. We don't like some of the fast-growing poplars, but maybe there are some good varieties. Would appreciate your advice! (Valley City, N.D.)

A: It is a good idea to have some tree diversity. The varieties you selected are excellent choices. As to the arrival time of these pests, I have no way of making any accurate predictions. They could start showing up in a couple of years or not for a few decades or more. Hopefully, by the time they arrive, the good minds that are working on their control will have something that we can use for protection.

Q: My husband sprayed my lilac hedge for weeds while I was on vacation. Now one of the lilacs is wilted. I have been watering it to see if it will come back. It has been two weeks now and it does not look good. The rest of the lilacs look OK. The hedge has river rock along the base, so he wanted to kill the grass that is growing on the rocks. What would be the preferred product to use to kill the grass and not my lilacs? Please help my husband get out of the doghouse! (e-mail reference)

A: Next time, take your husband on vacation with you so this won't happen again! Roundup would be a good choice for any kind of vegetation control in the setting you described. If he wanted to control just the grassy growth, he should get a grass killer that has sethoxydim as the active ingredient. If he should misapply the product, it won't harm your lilacs. The lilac that has been affected probably will recover eventually. Don't water too much because that may kill the lilacs quicker than the herbicide. Since your husband is occupying the doghouse, has the family dog now been given the run of the family home?

Q: I watered my spider plants with vinegar instead of distilled water by accident. Is there anything I can do to save them? (e-mail reference)

A: Give them two to three good waterings in a row to leach the vinegar out of the root zone.

Q: My mother has a Canada red cherry tree in her front yard that sends out suckers everywhere. Is there anything that we can do to get rid of the suckers without killing the tree? She has a newspaper article from your column from several years ago about this problem on a different kind of tree. At that time, you recommended a product called Sucker Stopper RTU. She has not been able to find it and someone told her that it probably would kill the tree if you treat the suckers. Please advise us as to what to do! Thanks. (Carrington, N.D.)

A: Sucker Stopper RTU wouldn't kill the tree, but she would go broke attempting to control all of that growth. The stuff is expensive and good for just one season and only stops the sucker growth at the point of origin. There is nothing I can recommend to use that will kill the suckers without the possibility of eventually killing the tree.

Q: While driving near the Green River in Stark County, I noticed some tall, thick shrubs with white flowers. Upon closer inspection, I believe they are Japanese lilacs. We live near that area, so I believe the soil type would be similar to ours. Are you aware of any local nursery that carries them? Is there any negative aspect to planting these as a decorative hedge/windbreak in a rural setting? (Gladstone, N.D.)

A: I can think of nothing negative about these plants in the setting you describe. As for any nursery that might be selling them, I can't help you there. Call around in Dickinson or Bismarck to see if there are any available.

Q: I received a kalanchoe and a spathphyllum plant for my mother-in-law's funeral. Can you plant these outdoors or do they have to be an indoor plant? Can they be set outside for the summer in a pot? Thanks. (e-mail reference)

A: At best, they can be set outside for the summer in a pot, but bring them inside well ahead of the first frost.

Q: We have a maple that for the first time (I think) has not produced helicopters. My husband disagrees with me and says that they don't produce every year. Do they or have I been imagining the bags of helicopters I've been sweeping up every year off our patio? If I am right and they do produce every year, why aren't they this year or are they late? Thanks! (e-mail reference)

A: They normally produce every year, but this year may be an exception because of the weather. Flower buds are more sensitive to low temperatures than leaf buds. With the snap back and forth in temperatures this spring, the flower buds could have been wiped out or they could be a little late this year.

Q: I planted some snow-on-the-mountain as a border plant. Is it necessary or OK to lay down mulch around the plants or is it better to leave it as is? (e-mail reference)

A: You would not be wrong following either practice. Generally, mulching conserves moisture and helps the plants get through the first year of summer stresses.

Q: I planted a bing cherry in my front yard last fall. This spring it was blooming and flowering, but all of a sudden the leaves and flowers turned brown and died. The rest of my fruit trees are fine. Any ideas as to what may have caused this? Thank you. (e-mail reference)

A: It could be trunk girdling by bunnies or voles or verticillium wilt, which is a vascular disease that blocks water-conducting tissues. Sorry, but you now have cherry firewood.


NDSU Agriculture Communication

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