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Published June 20, 2008, 12:00 AM

Spray plum trees when in full blossom

Q: We have several fruit trees in our backyard. One of them is a plum tree. For the first time, we have lots of plums on the tree. The problem is that the plums keep falling off as soon as they get close to maturing. The almost ripe plums also have little worms inside.

By: Ron Smith , NDSU Extension Service

Q: We have several fruit trees in our backyard. One of them is a plum tree. For the first time, we have lots of plums on the tree. The problem is that the plums keep falling off as soon as they get close to maturing. The almost ripe plums also have little worms inside. When should we pick the plums and how can we get rid of the worms? (Oakwood, Ga.)

A: You are too late for this year, except for picking up the fallen fruit and destroying it. Next spring, spray with an appropriate insecticide while the tree is in full blossom. Spray the tree again about 10 days later. However, do not spray if you see bees actively working the flowers.

Q: I have eaten potato leaves from my garden for years. I clean each leaf very well and then I chop the leaves to add to rice or sauce. Is it true that potato leaves are poisonous? Please help!

(e-mail reference)

A: The fact that you have asked me that question proves that rumor to be false.

However, poisoning is determined by the ounces or grams of toxin per pound of body weight. You probably have heard that if the skin is green on potato tubers, you shouldn’t eat it. The toxin known as solanine is a compound found in all members of the nightshade family, such as potatoes, tomatoes, peppers and eggplant. I am surprised that you didn’t find the taste bitter when you ate the potato leaves. If the leaves were not bitter and you didn’t feel sick, then you obviously did not suffer any poisoning. However, I cannot recommend eating the leaves from any of these vegetable plants because they contain solanine. There are many other choice greens to select from.

Q: I have a question about corn. We live in North Carolina. We planted the corn during the third week of March. The corn has tasseled, but a lot of plants don’t seem to have any cobs growing. Also, the stalks appear thin and reedy. Have you heard of corn growing without cobs? Did we fertilize too much or too little? (e-mail reference)

A: It sounds like the corn was starved for nitrogen. During my years of growing corn in several states, I found that when nitrogen was limited, the plants were stunted and yellow. It is probably early enough for you to get another planting in, but this time add some generous amounts of nitrogen fertilizer. Apply the nitrogen right after germination is evident and again 30 days later. This is a good rule of thumb to follow if you can’t do a soil test and analysis.

Q: Is it OK to put fruit that dropped from a tree into a compost pile even though the fruit has insects in it? I have three apricot trees in my backyard that never bear fruit. Do you know how old an apricot tree needs to be before it starts setting fruit? Also, if I try to plant some apricot seeds, do I need to remove them from the hard shell or can I plant the entire seed? I do have seeds that I have kept in an air conditioned kitchen for about a year. (Austin, Texas)

A: The compost pile is an ideal place for dropped fruit. The seeds can be removed from their hard shells or planted as is. I suggest moving the seeds you have into the crisper of your refrigerator for a couple of months to find out if they sprout. Put the seed in a damp sphagnum moss. While they can survive dry storage, there is bound to be some loss of viability.

Q: I just planted some marigold seedlings from the local nursery. The leaves on many of the plants are turning purple and have white spots. Is this a disease, bugs or a water issue? Please give me some guidance. (Long Island, N.Y.)

A: This sounds like a disease brought on by too much water. Marigolds are some of the easiest annuals to grow. Marigolds need full sun, ample water (drip irrigation is best) and soil that is well drained.

Q:I have a question for you about potentillas. We just purchased two red ace potentillas. The card said to plant the marigolds in a sunny or partial shade location. After reading some of the other e-mails, I’m getting the impression that full sun is best. We purchased them for a spot that definitely has more shade, but does get some direct sun later in the day. Will they grow under these conditions? (e-mail reference)

A: They will grow, but the flowering will be reduced somewhat.

Q:I bought two weeping birches and planted them in large containers. I was told that they grow well in containers because their roots don’t penetrate the ground very deeply. I also was given some kind of mystery tree that was hit by frost.

The person at the nursery wasn’t sure if the tree would survive. I also bought two lilacs. I planted all of them after soaking them in water the previous evening. In a few weeks, the lilacs and the mystery tree sprouted buds and have started leafing out. However, my weeping birch trees haven’t done anything. It looks like they had buds sprouting at some point, but they are dry and brown.

I’m afraid that these trees also were hit by frost. Could they be late bloomers?

The branches and roots seemed to be healthy when I bought them, so I don’t want to give up on them just yet. If they were hit by frost, is there anything I can do? Will they not bloom this year, but might next year? Any information you can give me would be greatly appreciated because I am new to this whole gardening thing. (e-mail reference)

A: It doesn’t sound too promising for the birch trees. They should have leafed out by now. Check the stems with your thumbnail to see if the cambium tissue is green. If it is, there is a chance they will recover. If not, they are dead, so you shouldn’t waste your time and hopes.

Q: I found your Web site while searching for information on lilac anomalies. I have a Donald Wyman lilac that blooms beautifully. Except for normal pruning to shape it, I haven’t done anything special to it. It has not had pest or disease problems. However, this year I see a number of branches that are flattened at the bud ends, but have blooms on both sides of the flattened branch. It looks quite bizarre and I don’t know what could be causing this. Do you have any idea why this might be happening and what I should do about it? (Boston)

A: This strange growth is due to herbicide drift from a neighbor’s yard or yours. Generally, this drift occurs when winds are more than 10 miles per hour or there is an atmospheric inversion. It also could migrate with the flowing water through or on the soil surface. The plant probably will outgrow this in future years, unless the herbicide is applied each year and the drift occurs.

Q: I just read through your Web section on web worms. I did not see any mention of a solution that a neighbor has mentioned. Last year, web worms devoured leaves in the Fort Worth and Dallas area. I am beginning to see them again this year. My neighbor says that laundry detergent around the trunk of the tree base will keep them off the tree. Have you heard this one before? (e-mail reference)

A: Never heard of it. If your neighbor is convinced this works, I see no harm in continuing the practice.

Q: I’m in a real dilemma. I accidentally sprayed shrubs and trees with Roundup. I thought I was spraying a chemical to get rid of bugs. That was four days ago.

I’m starting to see the leaves on my crepe tree turn brown. I washed the leaves as much as I could and watered around the trunk. I also applied some Miracle- Gro. I’m in panic mode and I need to know if there’s anything I can do. (e-mail reference)

A: I regret to tell you that, for the most part, the damage was done as soon as the application of Roundup dried. It is translocated throughout the system of the plants and does what you describe. If it is of any comfort, you are not the only one that has done this!

Q: My husband and I moved into a home three years ago that came with a large jade tree near a wall of the home. The tree is exposed to late afternoon sun and hot temperatures during the summer. There are a few nights of below freezing temperatures during the winter. I regularly take cuttings from the tree and plan to do so again. We want to transplant it to a pot, but have no idea what size pot to purchase. The jade tree has seven branches. Each branch emerges from the ground separately, so we don’t know if the branches are from a single trunk or individual stalks. If you can provide advice on how to transplant this jade plant to a pot, I would be very appreciative. (Sacramento, Calif.)

A: Your questions are better answered by a local landscaper who does this kind of thing. However, I will warn you that jade plants usually are better off being left alone rather than giving it too much care. If you plan to go ahead and have it potted, I would encourage you to take cuttings from the plant before you do it so that it will not be a total loss if the tree dies. Good luck!

Q: My family purchased a red maple three years ago. It looked fine when we purchased it and did well. However, in the spring of the second year, the leaflets grew, but they were droopy and never stretched out. We also noticed that the tips of the leaves turned black (burnt?) and there were little, round holes in the leaves. This year, it happened again. Also, the tree appears to be growing more horizontally (with an increase in side branches) than vertically.

My dad tied some of the branches together so that they now grow upward. Should he not have done that? Is that the reason why the leaves aren’t growing properly? I also read somewhere that it may be due to improper watering. My mother has planted flowers around the tree (perennial ground cover and phlox). I realize that we may be doing many things wrong, but what is the most likely cause and how can we save the tree? (e-mail reference)

A: Planting even a little too deeply can doom a tree and that sounds like what is happening to your tree. Also, the human tendency when a tree is not growing properly is to water it too much. Overwatering adds to the declining vigor. In addition, the planting of some perennials under the tree may have nicked or wounded some of the roots, which contributes further to the decline of the tree.

At this stage, there isn’t much you can do to save the tree. Sorry!

Q: How long do I have to leave the poles tied to an oak tree to help it grow straight? (e-mail reference)

A: If the oak tree is to grow straight, you need to remove the stakes and let the tree fend for itself. The movement will strengthen the wood and the tree will straighten itself out.

Q: I planted nine peach pits from peaches I ate last summer. Five pits were planted inside and four outside. I guess I don’t have enough to do. Of the nine, three pits sprouted. Two of the pits that sprouted were planted inside and one was planted outside. The one plant outside was murdered. It was death by garden trowel during a transplanting procedure. The other two were injured when an upper tier of plants collapsed on them. Both survived. When should the trees be planted outside? The trees seem too tender to handle the wind or a heavy rain. (e-mail reference)

A: There is a very important next step in your adventure. You need to harden the seedlings off. This requires an intensive babysitting role on your part. Begin by setting them outside in a somewhat sheltered location, such as an open garage, for about an hour the first day. Increase the time to 2 hours the next day and so on. Do this for about a week. Be sure the trees get some direct sunlight in the process. Then try a full day outdoors. Do this for about a week, but guard the trees from suffering through any severe weather, such as hail, high winds or a driving rain. After that two week period, they should be tough enough to tolerate moderate weather conditions and be planted outdoors in a permanent location. With normal care, such as regular watering (but not on a daily basis), protection against bunnies and marauding bands of insects, they should eventually mature into productive trees for you in about five years.

Q: Last winter, I stored my dahlias in a box filled with vermiculite in my basement. This spring, the tubers were very wrinkled. I assumed they were dead, so I tossed them. I have read about the many ways to store dahlias. I’m worried because I do not want to be buying dahlias every year. (e-mail reference)

A: You shouldn’t have tossed the tubers because that is the way they look after a winter of storage.

Gardening or houseplant questions can be directed to: Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or ronsmith@ndsuext.nodak.edu

Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations

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