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Ron Smith answers questions about plants, trees and gardens

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I am looking for a plant that likes to be cold in the winter and hot in the summer. It also would be great if it could be an indoor plant. If it is not an indoor plant, then it will have to be able to withstand frost because I live in Delaware. It gets cold here during the winter and sometimes it snows. During the summer, it can get very humid. (e-mail reference)

A: How about a hardy azalea? Visit some local nurseries or garden centers in your area to find out what they have to offer.

Q: We have been in our home for more than 10 years. When we moved here, we had a few spots of low-growing creeping ivy with light blue flowers in the spring. Needless to say, it has taken over the yard. Help! We hope we will be able to deal with it this coming spring. (e-mail reference)

A: See if you can locate a product known as Ortho Weed-B-Gon MAX weed killer for lawns or another one known as Trimec. Both have MCPP, 2,4-D and dicamba as active ingredients. Both work well in controlling this weed. Creeping ivy also is known as creeping Charlie or ground ivy. While spring is a good time to get after it, you likely will need a second application. It should take place sometime after the Labor Day weekend so that your control of the ivy will be much more effective and complete.

Q: I have read many of your answers about hollyhocks, but I'm afraid I have a few questions of my own. Could you recommend a few varieties that would bloom the first year, especially if started early indoors? The taller the variety, the better. As I mentioned, I will be starting my plants early in a grow room that I have built to get a head start on my gardening. If I'm planning to start 100 or so hollyhocks, what is the minimum size tray I can use without stunting the plant’s growth? I'm planning to start them six to eight weeks before the earliest outside planting date. This garden is going to be for my mother-in-law because it’s the one thing she wants very much. I also really want to make this happen for her because her husband passed away a few months ago. I appreciate any help and additional insight you can give me. (e-mail reference)

A: You are both a good and brave person for attempting this for your mother-in-law. I'm sure whatever you do will please her. Most of the modern hollyhocks are dwarf and doubles. From what I can figure from your question, you are probably going to be happier with the old-fashioned species of hollyhocks that get to more than 6 feet in height. I suggest going for the Alcea rosea varieties, such as fordhook giants, country garden and farmyard east coast. In choosing the planting tray, it all depends on how you approach taking care of the plants. The smallest trays would be acceptable, but keep in mind that the longer the plants stay in the smaller space, the more critical their watering and fertilizing regime becomes. Be sure to use pasteurized or sterilized potting soil. You also can use a soil-less media, such as perlite or vermiculite, to germinate the seeds. Good luck with your very worthy undertaking.

Q: I just purchased a new house and want to have my gardener plant a tree in the front yard. He recommended a weeping willow or a fruitless mulberry. He said that the roots will not come through the ground. I wanted a crape myrtle because I had one at my other house and the tree did not expose its roots. I also don't want a huge leaf mess. Between the two recommended, what do you think? (e-mail reference)

A: How about neither? Weeping willows and fruitless mulberries are notorious for dropping twigs and branches as they age. Both are sinks for just about any fungal and canker disease in the neighborhood. How about a thornless cultivar of honeylocust? Your gardener should be able to get a hold of those for you. The leaves mostly disintegrate or blow away with the wind when they fall in the autumn.

Q: What do I do with Easter lilies in the winter? I had them in the house at Easter time, but after they bloomed, they kind of died, so I put them outside. They came back up and looked healthy. They grew outside all summer, but when it got cold, I brought them back in the house. They are about 3 feet tall and droop. They don't get any sun and are turning light green. Where should I put them? Should I cut them off and not water the plants until spring? (e-mail reference)

A: Let them die naturally. Withhold normal watering. When the top is brown or withered, cut it off and store the plants in a cool, dry location for the winter months. Unless you live in the frozen tundra of the northern tier of states, most Easter lilies easily make it outdoors through the winter.

Q: I have a question about transplanting a small ash tree. There is a flowerbed that runs on the northern border of my yard about 20 feet in front of my house. A master gardener identified a small European ash tree that has started growing there. Ten feet to the west of it is a water hydrant. About 15 feet to the east are two spruce trees. To the southwest is a cedar tree. This flowerbed is the last thing that thaws in the spring because of its location. I am wondering if I should transplant it in the spring so that it would get more sun. Is this idea feasible? Will it survive? Will I have to worry about the hydrant pipes if I leave it there? The thing that concerns me most would be the ash borers. If I take the time to move it, will all the work be worth it if ash borers kill it? Is there anything that will prevent ash borers from attacking the tree? (e-mail reference)

A: Try it. The tree likely will survive in this location. I've pulled them out as weeds growing among spruce trees! Within your lifetime, I doubt that the ash borers will reach your ash tree. The nice thing about living in the Dakotas is the space between our landscape plants. Diseases and insects are slower to spread in our part of the country than in the more densely populated areas. If you want to move the tree, do so with a reasonable high level of confidence that the tree will survive. There are systemic insecticides (Merit) that can control ash borers. I wouldn't recommend starting to use it until the insect has been identified as posing a threat to the ash trees in your area.

Q: My bulbs are coming up with just leaves. These bulbs bloomed beautifully last year. I dug them up and let them rest for about six weeks in the refrigerator. After replanting, only the leaves are coming, but I know the stem is supposed to come out first. What did I do wrong? (e-mail reference)

A: The bulb did not make enough food through photosynthesis to produce a flower this year. The straplike foliage that follows the flower stalk should be allowed to stay on during the summer months until the first cool snap or very light frost. If nature isn't going to provide for this gradual transition, then bring the bulbs in at the end of the summer and allow them to dry naturally. Remove the dried leaves at that point. Refrigeration is not needed. In fact, refrigeration may be harmful to this tropical bulb. There is an excellent Web site to go to that is posted by Lisa Johnson, University of Wisconsin horticulturist. Go to to find all the information you need to get this bulb to rebloom.

Q: I am part of a community group looking to plant a “green wall" around a subway station in Toronto to act as a noise and visual buffer. We were thinking of planting arborvitaes because they are inexpensive and make great hedges. The area is a long strip of green about 4 feet wide by 300 feet long. The area is bordered on one side by sidewalk and on the other by a chain link fence and concrete platform. We would have access to water. The winters are cold and they do salt the sidewalks. The plants would get full sun. Do you think these trees are hardy enough to be successful in this kind of environment? How many plants and how far apart should they be planted for them to create a thick hedge? When should we plant them? How often should they be watered at first and then later once established? (e-mail reference)

A: Arborvitaes are hardy enough for your intended location. While Toronto gets cold, you are fortunate to have the modulating effect from Lake Ontario. The distance apart would depend on the cultivar you select or have available locally. The nursery you purchase them from would be in a better position to give you that information. You can figure for about 100 plants to cover this strip, especially if you get the upright varieties, such as the Brandon. Plant them when the ground thaws in the spring. Water the plants on a weekly basis unless a heavy rain has occurred or the soil is exceptionally well-drained. Whatever you do, don't let the soil root area become bone dry. If it is damp, that's OK. Allowing the root area to completely dry will result in plant dieback. After the first year, monitor the soil moisture to be sure it never dries completely. Have the soil tested. In most cases, no fertilizer is needed. Many people feel uncomfortable planting something without some nutrient augmentation. If that is the case, then use a product such Miracle-Gro at transplanting time and repeat in 30 to 45 days.

Q: I was looking at your suggestions about fairy rings. I recall a friend of mine a number of years back treating it with a copper solution. If my memory is correct, it was copper sulfate, but I could have that wrong. (e-mail reference)

A: I never have heard of copper sulfate being used for fairy ring problems. This is a basidiomycetes organism that is caused by a number of factors. Wetting agents might help overcome the hydrophobic character of a fairy ring. Fertilization and core aeration may do the trick to make it less noticeable. Copper sulfate is sometimes used to overcome algae problems in ponds or moss on container-grown nursery stock. Copper compounds often are used to prevent or slow down the decay of organic materials, such as burlap, in nursery stock.

Q: I recently transplanted a red oak from my yard to another location. It's been about two weeks and I'm seeing signs of stress (brown and some falling leaves). The tree is about 20 feet tall. I'm afraid I might lose it, so any suggestions would be helpful. (e-mail reference)

A: This is an unusual question to be getting in December. I'm assuming that you hired a tree spade operator to do the job. Unless the spade was an exceptionally large one, my guess is that most of the feeder roots were lost in the move. If the tree had been root pruned for a year prior to the move, then this could be transplant shock, which the tree will get over shortly. Were you told that moving oaks is not a good idea, especially at the size you mentioned? Red oak has a fleshy root system that does not allow for easy transplanting with any degree of success. Unfortunately, the only suggestion I can give you is to wait and see if the tree releafs next year. My bet is that it will not. At best, if will releaf, but have very few leaves and will continue to decline. Sorry!

NDSU Agriculture Communication

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