December 30, 2004

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: Is south Moorhead in zone 3 or 4? I have heard both from different sources. (e-mail reference)

A: Take your pick as to hardiness zones. You are in zone 4 if you live south of the interstate highway. Those living north of the interstate are in zone 3. If you believe that, I have a bridge I want to sell you. In reality, you can get a lot of zone 4 plants to survive our fickle weather with good cultural practices. The same applies to zone 3 plants. Most of the time plants in either zone expire because of our freeze/thaw cycles that often begin in late February and continue through March and sometimes into April, and not from our coldest temperature in midwinter. That’s why using good cultural practices is important.

Q: My very large Shubert chokecherry is showing severe signs of western X disease. This is the first time I have seen this disease in all of the years I have worked here. If I cut it down, will it come back with new healthy shoots or should we dig it out and replant with something else? This plant, with its purple leaves, has been such a pretty addition to our landscape. (e-mail reference)

A: This disease, mycoplasma, is the death knell of the tree. You are better off taking it out and replacing it with something else. There are no known control measures at this time. The disease likely is spread by leafhoppers.

Q: How can I start a plum tree? Can I start it by seed or grafting? (e-mail reference)

A: Seed is much easier and you get better results. Collect the pits from the plums and sow them this fall after the first hard frost, to a depth of about 4 inches. Winter stratification and moisture should crack the pit coat and most of the seeds should germinate After they are a year old, transplant them the following spring to their permanent location. Squirrels will be the biggest problem because they find the seeds and dig them up. Cover the seeds with hardware cloth until emergence.

Q: I’ve been trying to start a little window garden and so far it’s coming along great. Recently I took a clipping of a Christmas cactus from my neighbor’s plant. I set the clipping in water and now roots have developed. They’re about a half-inch long. When would be the right time to pot it? Should I do it now or wait for the roots to develop further? (e-mail reference)

A: It depends on the length of the cutting, which I am sure is longer than a half-inch. I would suggest waiting until the roots are about the length of the cutting, then transplant.

Q: I recently took down a Canadian cherry tree that had black knot. I left about a 12-inch stump. What is the best way to remove the stump? I would like to plant over that area again. Should I let it rot out? (e-mail reference)

A: You can rent a stump grinder and grind the stump and adjacent roots down to sawdust. Remove most of the sawdust and replant. Waiting for it to rot takes too long.

Q: I have been trying to grow a clove of garlic in my kitchen window, but every time the plant gets nice and tall it begins to fall over. When I dig in the dirt I notice what I think are fruit flies coming out of the soil. I think they have been eating the clove that the plant grew from because most if it is gone and the plant dies. How can I prevent this from happening? I’m trying to help my little boy grow a garlic plant and I’ve failed twice. (e-mail reference)

A: Have you considered showing him how to grow chives such as garlic chives? They are much easier to grow as a windowsill plant than a garlic clove, which needs to go through a cold period to be successful.

Q: Can broccoli leaves be eaten? (e-mail reference)

A: Yes, from a nontoxic standpoint, but why would anybody want to?

Q: We have a maple tree that is about 50 years old that we acquired when we purchased our home. It has been doing well for four years, but we have noticed that a few branches have turned completely white and are dying. The branches look like they’ve been painted. (e-mail reference)

A: It sounds like it could be a heavy scale infestation. I would get in touch with an International Society of Arboriculture certified arborist to spray the tree now and next spring before the leaves come out. This destructive insect can be controlled partially with Malathion or light horticultural oil followed by a lime-sulfur spray in the spring while dormant. You don’t want to lose this tree if it can be helped.

Q: What can be done to improve a yard that is horribly bumpy from earthworms? (Valley City, N.D.)

A: A temporary fix is to power-rake the bumps or roll them down with a ballast roller. A more permanent fix is to treat the lawn for grubs, which in turn impact the earthworms by killing off about a third of the population. Roll or power-rake the lawn after that.

Q: I don’t know what the problem is with my raspberries. I don’t know what plant type it is. They grow quite well and have a constant bunch of sucker plants, but, if they bloom, the blossoms dry up and bare no fruit. I transplanted some of the suckers last year to get a larger patch. They are doing well, but still no berries. The garden area is a former bean and corn field, which I farmed for 30 years. Where am I going wrong? (Tea, S.D.)

A: It sounds like they might have a virus or it could be the cultivar (variety) you selected isn’t suited for bearing fruit at your location. I would suggest getting rid of the plants and planting something that is more locally adapted. Usually raspberries produce abundant fruit for several years before a virus causes a decline in quantity and quality.

Q: We moved to Minnesota last year from the East Coast and planted (around June) a row of lilacs to create a border between us and our neighbor. They seem to be doing well. Do we need to do anything special for them this winter? (e-mail reference)

A: The lilacs will be able to stand anything the Minnesota elements can throw at them. Any action you may take is more threatening to their survival. If they were not “bedded” when you planted them, do so now. You don’t want to be mowing or weed whipping between these plants. If you have grass between them, carefully kill it off with Roundup and mulch over the area just prior to the soil freezing. Keep a 2- to 3-inch mulch-free area around each plant to prevent rodent and disease problems. The mulch should be organic, such as wood chips or shredded wood, and no more than 2- to 3-inches thick. Welcome to the Midwest! The best place in America to live!

Q: I had a schoolteacher stop by asking if I knew where to purchase buffalo seed grass or another native seed grass for a science experiment she is doing with her class. Can you help me? (e-mail reference)

A: She can find almost anything she would want for such an experiment in the “Seeds Trust High Altitude Gardens” catalog out of Hailey, Idaho. She can reach them by fax (208) 788-3452 or phone (208) 788-4363.

Q: I read the article in the paper a few weeks ago about the beetle or bug that is killing ash trees in Michigan and moving this way. Is it killing all the ash trees in those areas or will it eventually? Ninety-five percent of the trees along our street are ash. Should we consider cutting down some of the trees (they are probably too close together anyway) and planting some other shade trees? (West Fargo, N.D.)

A: I shy away from the idea of removing trees that are healthy. At the same time, I am in favor of species diversity. In this case, my bias would be toward species diversity against any future calamity. The Asian longhorned beetle is a voracious destroyer and, if the past is a reflection on the future possible successes at controlling this pest, it very likely will arrive in our area in a few years.

Q: I would really appreciate your help on an issue I am having with my ficus. It is an indoor plant that I’ve had for four months. I have noticed about 30 thin, small black bugs on the leaves. I also discovered some leaves curled over themselves and over several of the bugs. The infestation seems to be concentrated on one side of the plant. Is there anything that I can do? (e-mail reference)

A: Carefully prune off any leaves with the cocoons rolled up under it. Then get some Insecticidal Soap (do not make up your own solution) and spray it over the plant. Be sure to spray the undersides of the leaves. The material kills soft bodied insects on contact by dehydration. Next, I would suggest that you repot it in the next nominal size container. Gently knock the present soil off the roots and wash with tepid water. Replant in the container using fresh potting soil. Make sure the container is freely draining and pour off the excess water within 30 minutes of watering. Fertilize only when new growth is evident. Water it well, but only after the top inch is dry.

Q: I wanted to let you know about the spider plant that I have been trying to grow from seeds. I planted the seeds in a plastic cup with potting soil on Sept. 1. I had the cup sitting on a window sill for two weeks. I didn’t see any growth activity, so I brought the cup to work and placed it under a fluorescent light. The light is on eight hours a day, five days a week. I saw a little sprout coming up today after having the cup at work for about a week. I know you aren’t familiar with growing spider plants from seeds, so I hope this information is helpful to you or your readers. (e-mail reference)

A: Thank you! I couldn’t find any reference to starting spider plants from seeds. My references all state that the method of propagation comes from the planting of spiderettes, which I already knew. Glad you entered the realm of the unknown and were willing to share your success with me and the rest of the readers!

Q: My African violets are doing well. One has bloomed nonstop since last year. They are in my bird room, which is the only place I can keep them because of space problems. How do I clean the leaves? They are very dusty and have seed hulls and feathers on them. I shake them off a few times a week, but I don’t believe this can be a good thing. Can I put them in the shower and use a very low setting to rinse them off? I’ve heard you don’t want to wet the leaves with cold water, so I am assuming water on the leaves is a bad thing. I was going to use my dust buster or fan, but I don’t think the leaves could take it. I don’t think it would do much good because the leaves are velvety, so everything sticks. What type of soil do you recommend for these lovely show plants? (e-mail reference)

A: They get wet in nature, so go ahead and rinse off the leaves with tepid (skin-temperature) water, then place them in front of a fan for rapid drying. The potting soil should be designated “African Violet Potting Soil Mix,” which is available just about anywhere garden supplies are sold.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

###

Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu

BeefTalk

Prairie Fare

Plains Folk

Hortiscope

Market Advisor:

Crop

Livestock

North Dakota State University
NDSU Agriculture Communication
NDSU Extension Service
ND Agricultural Experiment Station