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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I just found your Web site as I was looking up blue spruce trees. I hope you can help me. We purchased a blue spruce tree from an area farmer. It is about 3 feet tall and in a plastic container. It looks very healthy. Can we safely plant it at this time of year? I planted one in May that is doing great. (Pennsylvania)

A: Now would be an ideal time to get the tree planted. It will not be producing any new foliar growth for the remainder of the season, but with the warm soil, rain and irrigation water, the roots will continue to grow until the soil almost freezes. This will help give the tree a good jump- start for next season.

Q: I just purchased a weeping willow tree and had planned on planting it in a few days. We have a low area in our yard that provides a runway for all of our neighbors’ yards to drain into a pond. This area is wet most of the summer. In the spring, it is wet and you cannot walk in it. However, as the summer progresses, the area dries out, but not enough where a garden tractor can mow the grass without getting stuck, so we usually only get a chance to mow that area to help dry it out once a year. Is that area going to be too wet for the willow? I would hate to have it drown even though I know that it loves water. Also, I read that the tree should be planted six weeks before the first frost. Should I plant it next year or do I still have time to plant now? (e-mail reference)

A: Plant it now and don't worry about the willow being hurt by the amount of water you describe. It should thrive!

Q: My tomatoes got off to a great start this year until they got about 2 feet tall. They started getting many wilted leaves. At first, it was only one plant, then another until all 18 plants looked the same. It took about a month for all the plants to develop the symptoms. They never did recover but never died completely. The problem could be moles, even though I did not see their trails. I also might have them planted too close to my leach field, so the roots are getting into the lines. I had a friend tell me it could be the walnut tree growing next to my garden. He says walnut trees may cause problems if they are too near a garden. (Keystone, Ind.)

A: Sometimes friends do offer sound gardening advice. In this case, your friend was right on! Walnut tree roots and leaves give off chemicals that are toxic, especially to all the vegetables in the tomato family, such as tomatoes, potatoes, eggplant and peppers. Don't plant in the same location again. Do your planting well outside the dripline of the walnut tree and in full sun. Your plants should do OK if you do that.

Q: I have two black walnut trees in my yard that are a mess. I hate to pick up nuts when they fall. Is there something I can spray on the tree to keep them from producing? If I can't get this problem stopped, I am going to cut the trees down. (e-mail reference)

A: The likelihood of getting a fruit-aborting hormone timed just right to prevent this from occurring is a shot in the dark. However, this is a judgment call on your part. I would suggest getting in touch with an International Society of Arboretum certified arborist in your community to see if he or she can fix the problem or knows someone who specializes in this type of tree care. Go to to reach someone in your area of the country. If unsuccessful, have someone come in and give you the lumber or veneer value of these trees before you have them cut down. Black walnut is highly sought after for furniture and other high-quality wood work, so you just might be able to make a little money when the trees are removed.

Q: I'd like to do something with some potentilla plants that either need pruning or to be sent to the Dumpster. They looked a mess all summer. I've read several comments that you made about pruning potentilla plants. You seem to lean toward pruning in the spring, no rounding off and, if needed, cutting them back to the ground to stimulate growth. I'm of the school that when I clean up in the fall, I like to get everything taken care of. If I cut them down to the ground now, would they still have that flush of new growth in the spring and do you think they will bloom that first year after a severe pruning? (e-mail reference)

A: Go ahead and prune them now because it won't hurt anything. They will flush out with new growth next spring but with very sparse flowering, if at all. The fresh foliage looks so good that you won’t even miss the flowers.

Q: When should I remove the wire guides that were put on my trees? I read that they should be kept on no longer than one year. Do you have any recommendations? (Boston, Mass.)

A: My recommendation is exactly what you said. Remove the guide wires after one year.

Q: I was wondering if you could help me figure out why all my carrots grew like this. They taste real good, but all of them grew all these extra legs, so it is a pain to clean them. I wanted to know if it is my soil, the weather or the seed. (e-mail reference)

A: Carrots form multiple roots (forks) when damage to the primary root occurs. Forking is associated with rocky, stony or heavy soils. Carrot fly damage also can cause this problem. Deep digging, the addition of compost and pest control will help reduce this disorder. Also, do not use carrot transplants because it will damage the root tips and cause the forking you have witnessed.

Q: I saw your posting on the Web about spruce trees. I am planning this weekend to move with a tree spade about 50 trees ranging in height from 6 to 9 feet. Any advice as to what to look out for and take care of when transplanting? How much water does one give the tree? (e-mail reference)

A: Don't drive down the road at 50 mph with the tree in the spade bucket. Keep it under 35 mph, with 25 mph being even better. Try to orient the trees in the same compass direction as they were in their original planting. Give them enough water to saturate the soil with the initial watering. I can't tell you how much because it all depends on your soil type, slope and exposure. Prewater the hole the trees are going to be placed in before setting the trees. That way the chance of surrounding dry soil pulling water away from the roots will be eliminated.

Q: I'm hoping you can help me with my dilemma. I purchased a cherry tree this spring but didn't plant it outside. It's doing well in the house in a pot. I'm wondering if it needs to freeze during the winter or if I can leave it in the pot and plant it outside in the spring. It's a carmine jewel cherry and is supposed to do well in our area, but I'd rather not put it outside now because it never has been outside. Any information you can give me will be greatly appreciated. (East Grand Forks, Minn.)

A: Your tree needs to go through a cold period to survive and thrive. It is a temperate zone deciduous tree that needs the cycles of nature. I suggest placing it outside now, container and all, in a protected location on your property. When spring arrives and the frost is out of the ground, pull the plant up and place it in a permanent location, but take off the pot. There is the risk of losing it due to extreme weather conditions, but it is guaranteed to be lost if you keep it indoors.

Q: My jade plants sometimes are infested by something that leaves white spots. I'm not sure what it is, but spraying with 100 percent alcohol gets rid of the problem without harming the plants. I spray the plants until they are dripping wet and repeat the spraying a few days later. I don't know if it matters, but I'm using ethanol (ethyl alcohol), not isopropyl alcohol, which is the main ingredient in rubbing alcohol. (e-mail reference)

A: Thanks for the information. Apparently the ethanol is friendlier to the plant than isopropyl, which only should be used as rubbing alcohol.

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

NDSU Agriculture Communication

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