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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: I have nine clumps of river birches in my yard. This winter we had an awful ice storm that broke the tops out of four of the clumps. I had two trees taken down out of one clump. During the weeks after the trees were taken down, the stumps were almost pouring out a substance. Is this sap? It is colorless, odorless, tasteless and feels like water. (e-mail reference)

A: This is sap pressure coming from the roots. It will stop when spring arrives. If you were to have a chemical analysis made of the liquid, you would find it rich in carbohydrates, which are used in the surge of spring growth.

Q: I have a dieffenbachia plant that has been moved and transplanted many times during its six years of life with me. The plant has large stalks, but no leaves to about the 4-foot level. Will it ever grow anything lower? It has gotten so tall and top heavy that we’ve had to stake and tie the stalks. The plant is in a deep, large pot. It has reached the second floor banister and is going strong. I have put a tiny dieffenbachia with it to make the bottom look more appealing. Please give me some advice as to what to do. (e-mail reference)

A: Cut one of the stalks back to about a 4-inch nub. This will force new growth to break from the base of the plant. This will give it a more attractive and balanced appearance. As that one fills in, you can do the same thing with the other stalks.

Q: I saw your Web site and read much of it, but couldn't find any situation similar to mine. It's a crazy story. Two weeks ago, a wild cat got into our house. As we tried to herd it toward the door, it ran rampant throughout the house. On its way to climbing my shear drapes, it bounced off my mature jade tree. It is not the periphery damage I am concerned about, it's the trunk. About half way up the trunk, I found two weak spots a couple of inches apart where the tissue is denting in and wrinkled, but still very firm. I am able to wiggle the trunk slightly and believe it to be broken, but not all the way through. Should I leave the plant alone to see if it heals or should I bandage, prop or prune it? Is there something I should have done already? This is a great, healthy plant. (e-mail reference)

A: Well, you have the distinction of asking me a jade question that I never have had before! Based on what you've told me, I would suggest a soft bracing of the trunk to be on the safe side. This means that the attachment should not be inflexible, such as a twist tie. Use an elastic brace, such as a rubber band or budding rubber to hold the brace. Just out of curiosity, how on earth did a wild cat get into your house?

Q: Last year there was a program on television on the preventive care for birch borers on two species of birch trees. We have one of each variety. Both are young trees. We wish to treat the soil around the tree to protect it. What is it that we put in the soil and surface around the tree? What dosage do we use and how far out from the trunk of the tree should we place it. We live in a small town, so I need to know the product name and where to buy it? Thanks for any help you can give us. (Burke, S.D.)

A: The product is Bayer Advanced Tree and Shrub Insect Control, which also is known as Merit insecticide. It is a soil drench that is poured around the base of the tree in early to mid-April. Explicit instructions are included with the insecticide. Be sure they are carefully followed. Any garden center tuned into the 21st century should have it available.

Q: I planted an Austrian pine years ago. It grew nicely last year and looks ready to do even better this year. While researching its potential pests, I discovered it is not considered hardy for our area. Have I just been lucky the past two winters? Also, are rabbits much of a pest to this particular pine? I've had it protected, but as it is growing nicely, I'll have to expand the protection or just let it fend for itself. We sometimes do have a rabbit or two in the area. (West Fargo, N.D.)

A: You got the wrong information because it is hardy to zone 3. With climate change, that will improve. Enjoy and don't worry!

Q: I am renting a house in Concord, Cali. The landlord who owns the house told me that we had an apricot tree in the backyard. The tree is very close to the house and last year it was infested with aphids. This year it seems to be doing OK. I was wondering how I could tell if it's an apricot tree. Do apricot trees normally produce sap? Is there anything I could do about the aphids if they come back this year? The tree has no signs of bearing fruit, but I think it's too early. (e-mail reference)

A: Aphid control is best practiced with an application of dormant oil spray before the trees leaf out. If you were told it is an apricot tree, then you have to believe it until it bears fruit to prove otherwise. The sap that was annoying last year came from the aphid feeding activity. It will occur on any tree that is infested with aphids or other insects with piercing-sucking mouth parts.

Q: I'm working on an article for ways to spruce up or decorate a porch or balcony. The first thing that came to mind was plants and miniherb gardens. Could you offer any suggestions for hanging or standing plants and/or little herb gardens that will fare well in the Brainerd area and possibly would provide a splash of color? Any input would be greatly appreciated. Thank you! (e-mail reference)

A: Herbs, such as lavender and hyssop, are colorful and attractive to butterflies and hummingbirds. Spreading flowers, such as wave petunias or ivy geraniums, are excellent for hanging baskets. There are flowers, such as portulaca and vinca, that do well in hot, sunny locations. I grew some diascia last year and was impressed with their staying power through the growing season. How about the chilly chili ornamental/edible pepper? It is a colorful, prolific producer that can be eaten without the consequences of heat.

Q: We planted 200 trees in 2005. Some are green ash. We are wondering if the trees should be pruned this spring. Some have begun spreading out because deer have been nibbling in them. (Bismarck, N.D.)

A: Now would be a perfect time to prune to get them started on the shape you want them to eventually take. You need to do something to control the deer activity or else your best efforts will be wiped out. There are plenty of repellents to select from.

Q: Is Canada green grass seed mixture a good variety to plant? (Fargo, N.D.)

A: No, no and no! And this goes for the Zoysia grass promos, as well, for all who want to ask me. These advertisements make grasses such as this sound like the universal panacea by saying the seed germinates rapidly, requires little to no mowing, no water and whatever else they promote to get people to buy the seed. NDSU, as well as other land-grant universities, carry on research dealing with countless species and cultivars of turfgrass to determine which ones will make good home lawns or athletic turf. I assure you that these are not recommended for our area. Let the Canada green stay in Canada and Zoysia stay in the South. Save your money and time to spare yourself frustration down the road.

Q: I received a tree last fall from some people who didn't have room for it anymore. They had it outside all summer. I think it got too cold before I got there to get it. It has lost a lot of branches and needles. A lot of the remaining needles are brown. I've been misting it every day and turning on a humidifier for a while. The humidity in my house has been around 70 percent all winter. Is that high enough? Can you tell me what to do to help the tree? My husband wants to know if it will grow if we cut the top off and plant it. (e-mail reference)

A: There is not much more you can do. If the tree is going to recover, it will with the care you are giving it. Cutting off the top and planting it will not work because it will not root.

Q: We have mature cedar trees planted on our property line. If we trim the branches back to the property line, will we end up with stubs or will the branches fill in to make a hedge? I would appreciate any ideas you have on this subject. (e-mail reference)

A: If you trim the trees back to bare stubs with no green leaf tissue remaining, they will not fill in and remain branch stubs.

Q: I built a new home and had some topsoil hauled in for my yard last fall. The soil looked fine at the time. Now it appears as though there may be some alkali in it. The areas of the yard that are the driest have a white, crusty substance on the surface. The wet dirt is black. Is it alkali? If so, what can be done about it short of removing it? I live on a river bottom with sand, so black soil is needed for a lawn. (e-mail reference)

A: Find out how bad the soil is by having the local land-grant university test it. Most have a soil testing lab. For a nominal fee, it will provide you with a soil test for pH, P, K, soluble salts and organic matter content. I suspect that you will find the pH to be quite high (8 or more), and also a high soluble salt reading. I'm also willing to bet that the soil is very poorly drained. You can try adding copious amounts of organic matter to the soil, along with a generous amount of sand, to correct the problem. However, if that is needed, you probably are better off getting this stuff hauled out and replaced with some decent topsoil. Get it tested before you have it delivered this time.

Q: We have arborvitae screening our entire backyard. I don't think the prior owners watered very well. However, the arborvitae that borders another neighbor's yard is doing well, presumably because they were able to utilize water from his watered lawn. On another side, though, the neighbor installed a gravel strip several years ago along his side of the fence. These arborvitae have become thin on the lower half. The top 3 feet are thick and bushy (maybe because that is relatively new growth and we have been doing a good job of watering). Is there any way, even with meticulous pruning, that the lower half of the sparse arborvitae can be made to bush out or at least to branch out to the left and right sides (which would provide more screening) versus branches/foliage growing right toward the house (which doesn’t provide much screening)? If so, any details on how exactly to prune would be much appreciated! (e-mail reference)

A: You are an ambitious man, but save it for something that will reward your efforts! Unless these trees get generous amounts of sunlight, water and nutrients, chances are they will remain wimpy, thin plants in those respective areas. Sorry! You might be better off digging them out, reworking the soil to support better growth and planting some fresh arborvitaes.

Q: We have a large batch of raspberry bushes. When is the best time to prune them and how far back? This is a second year we’ve had the raspberries, so we hope to get some berries this year. (Gering, Neb.)

A: Now is the best time to prune. Prune them back to about breast height. Thin out to the base of the plant anything that is spindly. Do something to support them or else they will be pulled over by the spring growth. If you do that, berries should set for you.

Q: I live in Austin, Texas, and have an ornamental, purple-leaf plum. It gets full afternoon sun and morning shade. My problem is that I noticed it is oozing brown sap that forms a big bubble on the bark. The bubbles are on the base of the main trunk. I busted one open and found a jellylike substance inside. (e-mail reference)

A: That oozing usually is a good sign of borer activity. Once started, they are extremely difficult to control. Judging from the location you described, the tree likely will be girdled soon, which probably will kill it.

Q: I've had my dieffenbachia for about a year and a half. It started as two stalks and grew two more. I moved last fall to an apartment with no light, so I have to keep the lights on during the day when I'm home. The plant gradually started producing fewer and fewer leaves until there were only a few left. I decided to bring it to work where it could get more light. It was cold and windy the day I brought it in and by the time I got to the building, all the remaining leaves had wilted. I left them on for a few days before I peeled them off. This was several weeks ago. There has been no new growth and the tops of the stalks are turning black. (e-mail reference)

A: Bury the remains and start again. There is no point in wasting time attempting to get this poor thing back to life.

Q: I have two small evergreens that I planted at the same time. One is doing great, but the other is brown and dying. However, the dying evergreen has what appears to be new needles growing now that spring is here. Is there a chance it will come back or should I give up and replace it? (e-mail reference)

A: I'd give up and replace it. You may be witnessing a last gasp of growth with spring's arrival. Even if it does live, it never will be anything to be proud of.

Q: I have some evergreen-type shrubs growing on a hill in front of my house. The shrubs look very nice after I get all of the grass and weeds pulled out, but it is a lot of work. I was wondering if there was a weed and grass killer that I could use to make it easier on me, but without killing the shrubs. (e-mail reference)

A: Once you get the weeds pulled, you can apply a product, such as Preen, that will control most of the weeds without harming the evergreens. Visit the local garden store in your area and you'll find several products on the market. Be sure to check the label for evergreens and closely follow the dose guidelines.

Q: I discovered a sprouted seed in an apple. I planted the seed in a pot at work and two weeks later, to my surprise, I can see a tiny stem and three leaves. I would like to grow this tree. When and how should I plant it in the ground? How deep should I plant? Should it be in a sunny or shady spot? How often should I water it? (e-mail reference)

A: Allow it to grow in the present pot for about two more months. Give it plenty of sun and water. Then carefully knock it out of the pot and plant it in a sunny location at the same depth. Do not remove the soil from the roots. By the time you do this, the roots should have grown to the outer edge of the pot and should hold together quite well. Good luck!

Q: Do you know if dieffenbachia is harmful to cats? I just received a plant and the donor said it might not be good for my cats. Any ideas? (e-mail reference)

A: If your cats eat any of the leaves, they are very liable to suffocate from the closing of their throat. I would keep it well out of reach of the cats or don't keep the plant.

Q: I wrote you last year about my peach trees south of Jamestown. They made it through the winter. I was scared they wouldn't because of a week with minus 30-degree temperatures. The deer and rabbits left them alone and they have the same branches they had last fall! I have more questions now that they made it through the winter. The trees are starting to bud, but it is only March! I know this is why we don't get a lot of peaches because of the early budding. Do you know if there is anything I should be spraying on the trees this spring or do I leave them alone? Also, I have been reading a lot about pruning the trees, but I don't know when I should. Do you prune them now that they are budding? Is it too cold for it? Do you wait until they have flowered? How many branches should I leave? I really appreciated the help last year. I did buy some deer repellant and kept the bark covered during the winter. I don't know if the repellant worked, but the deer left them alone. I promise if I grow a peach, I will send you one. (Jamestown, N.D.)

A: Nice going. I hope the trees make it so I can say that I've eaten a North Dakota peach! At this point, leave them alone. Once they start budding, they shouldn't be pruned. If a cold snap is forecast, try covering them with a sheet or turn a sprinkler on them. Since the trees are so young, allow the branches that are there to remain to help build a strong tree stock. In another year or so, prune them as you would any fruit tree to give them maximum light, air movement penetration and ease of harvest.

Q: I have a cactus that belonged to my mother. I have no idea how old it is, but it has to be at least 25 to 30. It is very woody at the base, not extremely filled out and somewhat leggy. During the last year, it has become very limp and some of the leaves are a poinsettia pink. I repotted it for the first time in probably five years. I may have jumped to too large a pot. Will that be a problem? It is not looking any healthier. What should I do? I hate to loose it because my mother passed away this year. I am attempting to start another plant, but it has not shown any growth. (e-mail reference)

A: For information, go to I don't know what else to tell you except to keep trying to get something rooted from one of the fronds.

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
Prairie Fare: Prairie Fare: 5 Tips to Evaluate Health Information in a High-tech World  (2019-05-16)  Reliability and trustworthy information is important when making health decisions.  FULL STORY
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