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Ron Smith answers reader's questions about the world of plants, trees and gardens.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: When growing onions from seed, do you trim the green tops before transplanting in the garden? Is this done a couple of times while they are growing in the greenhouse? I have found conflicting opinions. (e-mail reference)

A: According to my colleague, Harlene Hatterman-Valenti, the answer is no. The leaves are left on in full regalia to maximize photosynthetic activity for the developing onion bulbs.

Q: I got a branch from an apricot tree that I put in water. It seems to be doing fine. After it roots, I would like to plant it in a pot and keep it pruned so it won’t grow too large. If everything goes according to plan, will it bear fruit? Should I bring it indoors for the winter? (Toronto, Ontario)

A: Did you get the branch from a tree in Toronto? If so, ask the person what care he or she gave the tree. If it came from a Toronto source, you should keep it outdoors and it should bear fruit. If this is a branch you got from somewhere outside your region, then the question of survivability is up for grabs.

Q: While researching evergreens, I came across this query from a person in Mott. "We have our own well with brown water and an underground irrigation system. Watering was set for 4 a.m. twice a week. This gave the trees an inch of water a week. Now the trees look as though they are drying up." As a chemist who tested local wells for more than 10 years, your deduction of salt burn may be accurate, but may not be from salt spray from winter deicing. Most of the brown well water in southwestern North Dakota has a chemical composition with very high sodium and very low calcium/magnesium (hardness). The sodium can range from 200 to 1,000 parts per million (ppm) or more and the hardness is usually less than 2 to 5 ppm. It essentially is softened water. The brown tint usually is tannins or sometimes iron/manganese. This water also tends to be very alkaline (pH of 8 or more). (e-mail reference)

A: Thanks for the compliment about the column and the information on brown water. I appreciate it very much. You are correct about the alkalinity. I have seen some water testing out at a pH as high as 8.8! That really is elevated and poses a problem for growing just about anything!

Q: I purchased a tree and later discovered it was labeled as "needs a pollinator." What exactly does this mean? (e-mail reference)

A: The tree needs to have another tree of the same species, but of a different variety or cultivar, for fruit set. For example, an apple tree known as Haralson would produce better if another apple variety, such as sweet sixteen, is nearby. If anyone in your neighborhood has different varieties of the same species that you do, that usually is sufficient for pollination. Without it, the fruit set would be very sparse or nonexistent.

Q: I have had a hoya for about 20 years. I got it from the Welcome Wagon lady when I moved to a different town. It has grown very little since then. In fact, it only has grown one more stem since I got it as a starter plant. It never has bloomed, but it seems healthy enough. It doesn’t drop leaves very often. Until recently, it hasn’t been in a sunny location. Could that be the reason why it hasn’t done well? I am now in a new home with sunny rooms and I have it sitting in an east-facing window. I would love to get it thriving and blooming! Any more tips on what I can do to get it growing? (e-mail reference)

A: You should see the difference between maintenance living and thriving growth very soon. The sunlight should do it, along with the care you have been giving it. If you don't see some response in six to eight weeks, dump it! You may have a bad specimen that isn't worthy of your attention and concern.

Q: Is there anything you can spray on dandelions this time of year that will kill them in the lawn? I enjoy your column in the Jamestown Sun. (e-mail reference)

A: Lots of stuff is on the market that will have an impact. The choice is yours, but Weed-B-Gon is a common product on the market. People get satisfaction from seeing the flowering stems curl up after spraying. Some of the older plants will recover and need a reapplication around the Labor Day weekend. The kill is more effective at that time. Thanks for the compliment about the column!

Q: I have an old silver maple. This year, the leaves have not opened up fully and seem to be full of seeds (the little helicopters). My tree trimmer tells me the tree is in distress. He says it might have something to do with the landscaping I did last year, but I know for certain that there was no digging around the tree. Also, pieces of bark are falling off the lower part of the trunk. Is my tree sick or does it need fertilizing? (e-mail reference)

A: Your tree trimmer is correct in saying the tree is in distress. That is why you have the heavy fruiting of seed. You need to get an arborist or someone else competent enough to make an accurate diagnosis of your tree. It should be determined if the tree can be saved or removed to prevent it from becoming a hazard. Generally, when trees get to this state, it is a continuous downward slope that leads to the collapse of the tree.

Q: I find your Web site interesting and educational. We have a Canada red cherry. During the last two to three years, we have been getting black knots on several branches. I have been cutting off the smaller branches that are affected. However, now I have a major branch that has these knots. Is this tree doomed? If I have to replant, what tree do you recommend as a replacement? We need something that is drought-tolerant, but don’t wish to have evergreen trees. (Lisbon, N.D.)

A: The northern acclaim would be a good replacement for this poor, diseased cherry. Once black knot gets started, it is very difficult to control. At this point, you would be better off replacing the tree.

Q: I stumbled across your Web page addressing questions on lindens and basswoods. I would appreciate it if you would answer several questions I have about our newly acquired American linden boulevard that was planted in my front yard by city workers. The tree is pretty, even at its young age. However, after reading of some of the undesirable traits of this tree, I am concerned that the litter from this tree may be an issue. We have a basketball hoop, so we often use our cement driveway as a play area or gathering area, especially when the winds are up and we seek shelter from our backyard. I’ve also read that lindens have a massive root structure, so I am concerned that this could cause issues with our cement driveway and exposed aggregate trim. Someone told me that these root systems can and will push up cement. We also have an underground irrigation system. Do you think the roots could affect the irrigation system negatively? I also read that lindens do not do well with general applications of weed control near their root structure. (e-mail reference)

A: Lindens are no worse than any other tree. For example, I have a linden growing about 6 feet from the edge of my concrete driveway. It also is surrounded by an automatic irrigation system that has been there for almost 20 years. On occasion, herbicides were used under the tree's canopy to control unwanted weeds. This is about the same situation you just described, but I have not had a shred of trouble. No matter what tree the city installs, the potential is there for all the problems you mentioned and then some. Much depends on the health and vigor of the tree at planting and subsequent care thereafter. Knowing something about city forestry policies, the foresters typically plant trees that are not going to give them a lot of trouble. The linden selection will provide a nice, visual impact on the community environment.

Q: I have some questions about moving trees. An acquaintance has a row of spruce trees. He planted these trees too close together on purpose because he was expecting some of the trees to die. However, they all lived and now he wants to get rid of every other tree. He is willing to give us these trees free of charge. We would hire a professional to move them. Is now a good time to move them? Will our acquaintance have to worry about the digging causing damage to the remaining trees? I appreciate any guidance you can provide. (Bismarck, N.D.)

A: At this point, if the trees are intermingled, there is no way a tree spade can get in there without doing some damage to the remaining trees. Hand digging a rootball and burlapping it would be better for the trees being taken and the ones left behind. The tree roots also will have become grafted together in most cases, so such a move would be damaging to all the roots attached to each other. For moving the trees, about a month ago would have been better than now. Is it a good idea to move them? It depends on your acquaintance’s attitude to the possibility of damage to the trees left behind and the tree spade operator you are hiring. Being offered free trees is a good deal, but a wasted one. It is like buying a new car with a tank full of gas, but, when the tank is empty, there is no gas available, so what good is it? If the trees die after being moved, then it was a futile and expensive effort on your part. If your acquaintance's trees that are left behind decline and die as a result of this move, you've also alienated a good friend or relative. Based on what you have told me and what my mind's eye can see, I wouldn't do it. It is better to have him cut the necessary trees out at the stump and offer them as Christmas trees this December and keep the friendly relationship.

Q: I cut numerous lilac flowers so I could bring them to work. I placed the flowers in a vase with regular water, but within a few hours, the flowers started to wilt. I clipped some of the flowers with a knife and others with a pruning shear. What is causing this to happen? (e-mail reference)

A: Starting in the early morning, take a bucket partially full of warm water out with you when you are going to harvest some flowers. Water is taken up from the cut end of the flowers, not the sides of the stem. Select flower heads for harvest that have some florets still unopened. To harvest the flowers, make a slanting cut with a pair of hand pruners. Immerse the cut ends into the water immediately. When you return indoors, have a vase of warm water available and take the cut flowers out one at a time and make another slanting cut. Insert the flowers into the vase immediately. This procedure usually helps the flowers stay firm for about two days. That is as good as I've seen it. Perhaps a reader will know of a better way to keep the flowers fresh for a longer period and will drop me a line.

Q: We have a maple tree that we planted about eight years ago. Our yard faces south. This year, the leaves look like they need water because they look wilted. We have what look like pimples on the back of the leaves. Someone at the gardening store told us it was the temperature changes causing this problem. Please help because I would hate to lose the tree. (e-mail reference)

A: This sounds like verticillium wilt if the whole tree is affected. If it is, there is nothing that can be done to save the tree. If it is a weather-related problem, the tree should pull out of it in a couple of weeks with a flush of new growth. Otherwise, I don't know what the problem is.

Q: I bought a beautiful spider plant and hung it near a southwest-facing window. I didn't do anything to the plant until today. I didn't water the plant because it was raining the day I bought it, so I didn’t want to overwater it. Now I have brown ends on the leaves. I'm really worried. What should I do and what do you think is the problem? (e-mail reference)

A: The brown leaf ends are salts, such as fluoride, sodium and chlorine, which accumulate in the plant and cause this tip browning. It will not hurt the plant. You can water with rainwater or distilled water. The new leaves that emerge should be free of the brown tips.

Q: I have a lawn that was sodded last summer. It took very well and looked great in the fall. This spring, I discovered I had voles that had tunneled through the lawn, creating bare patches where they ate the grass down to the roots. What is my best plan of action to revive the lawn? Fertilize and water and hope it grows back? Should I seed areas as needed? (e-mail reference)

A: You are on the right track, but you shouldn't need to add seed. Vole damage is temporary. By this time next month, everything should be back to normal.

Q: I had a heritage river birch planted in my front yard last fall. Most birches I see (even young ones) have a lot more bark exposed toward the bottom. Our birch has little branches all the way down to the root. Can we prune the bottom portion of the tree? (e-mail reference)

A: Now that the tree has leafed out, go ahead and cut off some of the smaller, lower branches. They will end up being negative contributors to the carbohydrate production of the tree. Otherwise, it is a very nice tree. Congratulations on making a good selection.

Q: I just discovered your Web site while searching for lilac information. I bought a common lilac a few weeks ago. I planted it a few feet from my peach tree. However, I just found out that my peach tree has leaf curl, so I'm worried my new lilac will get infected. Should I move the lilac to another place? Should I spray a fungicide on it? (e-mail reference)

A: Start by finding out what is causing the leaf curl on your peach tree. Your problem could be caused by insects or a fungus disease. Generally, these pathogens or insect pests are host specific, so they do not spread to other plants. Moving the lilac now would be too stressful, so the plant could die.

Q: What is the best propagation protocol for thuja occidentalis? I’ve had a hard time getting mine to germinate. This time I cell-seeded them in trays (after stratification), lightly covered the trays, put them under a UV light, turned up the temperature to the 77- to 80-degree range and misted them often during the day. I got excellent germination, but what should I do now that they are coming up? How often do they need to be watered? Should I continue misting them? Is it possible to transplant the plants I thinned-out and what is the best way to do this? (e-mail reference)

A: Get some pasteurized or sterilized potting soil and 4-inch pots or containers. Transplant them at your earliest convenience, without allowing the roots to dry out. Once the seedlings are a few inches tall, you don’t need to mist them anymore, but don't allow them to dry out completely. Yes, you can plant the thinned out plants the same way.

Q: I was wondering if I could plant crabapple and apple trees together. I was worried that the fruit of the apple tree would be affected. (e-mail reference)

A: Not a problem, so go for it.

Q: Our neighbor has taken down several trees that were infected with carpenter ants. They moved to our apple tree and completely gutted it. Unfortunately, I believe our pear tree also has been invaded. Although there appears to be a sawdustlike substance at the base of the tree, I am confident the problem is ants, not termites. Is the pear tree a goner or can it be saved? Last year's leaves and fruit had black spots. The pear tree is tall, lean and 40-plus years old. (e-mail reference)

A: Carpenter ants are interested in rotting wood, so their interest is in older trees where the core or heartwood is rotted. You have been fortunate to have a pear tree last as long as this one has, but I think the time has come to have it removed. With heartwood rot, depending on the size of the tree, it is prone to being a hazard during a strong wind, which also could be a physical hazard to property and people. (e-mail reference)

Q: Our apricot tree bears fruit, but each year the fruit gets black spots on it and, for the most part, the fruit never ripens completely. The fruit just falls off the tree. Will Sevin spray help this spring? This tree has been overlooked for many years and we never have eaten the fruit because of its appearance. Perhaps this year will be different with a little bit of your help. This apricot tree is more than 30 years old. (e-mail reference)

A: The apricot tree has some kind of fungus that is causing the black spots to show. It may be too late to apply an effective spray. Visit a local garden center or nursery to get what is known as a fruit orchard spray to control disease. Apply it according to the directions as soon as possible. Generally, these sprays need to be used at blossom drop time. Sevin is an insecticide that is not effective for any direct disease control.

Q: My mother has some climbing rose bushes that were hit by a brutal frost in 2007. Last year and this spring, the leaves are yellow and most of the canes are dried up. Only the tips of the canes have leaves. The roses bloom on my mother's birthday (June 2). My mother recently passed away, so it is more important than ever that I try to keep these climbers healthy and growing. Obviously, I have no idea what kind of climbers they are. Your assistance is greatly appreciated. (e-mail reference)

A: From what you have told me, all I can suggest is a hard cutting back to see if the plants can send up any new growth. Obviously, the current situation is not going to result in anything that is going to sustain them. Hopefully, there is viable tissue in the lower quadrant of the plant that will break dormancy and send up flowering stems this year.

Q: I live in southern Ontario. There are a lot of deer that live here and some were eating our new nut trees. Two farmers told us to place a bar of soap on the trees. It worked! Each spring, we purchase the cheapest bar of soap we can find. We cut it in half using a band saw and drill a hole in the middle and tie rope on it. We then hang it on the tree. We still see the deer in the trees, but now they eat the grass and leave the fresh buds alone. Hope this information will help someone else. (e-mail reference)

A: The deer must be more polite and respectful in Canada than they are in America! The only sure thing that has worked that I have seen is exclusion fencing. But, like you, other people have sworn to the success of their particular product or method. Someone else may try the same thing, but fail. If it works, great, so keep it up.

Q: I have a hansa rose bush. The last few years it has had a couple of branches that produced just a couple of pale, pink roses. I can see that parts of the bush are different from the hansa variety. I am wondering if I should try to start a new bush or if I should try to cut out all the branches that don’t look like the hansa variety. I like hansa because it is hardy and does well in our cold climate. It also has done well during the hot weather that we have been having the last few summers. (e-mail reference)

A: Cut off the parts of the plant that are not the hansa variety. What you have is a genetic chimera or a growth from the rootstock.

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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