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Published May 07, 2010, 12:00 AM

Most plants have no fertilizer preferences

Q: Is it too early to fertilize perennials and trees? Last year, we did some landscaping and used 10-10-10 and peat moss. We then covered everything with mulch. This spring, should we sprinkle 10-10-10 at the base of the plants or just use Miracle-Gro mixed with water?

By: Don Kinzler, INFORUM

Q: Is it too early to fertilize perennials and trees? Last year, we did some landscaping and used 10-10-10 and peat moss. We then covered everything with mulch. This spring, should we sprinkle 10-10-10 at the base of the plants or just use Miracle-Gro mixed with water? (e-mail reference)

A: Apply any fertilizer when the plants are beginning active growth. Since you worked in the 10-10-10 last fall, there is no need for more fertilizer. You can use any or all of those fertilizers as you see fit to do so. Except those plants that require constant acidity in the soil, most plants don’t have any preference for a particular fertilizer. The liquid applications have the advantage of addressing any visible nutrient deficiency immediately because they are quickly utilized by the plant.


Q: I am wondering if it is feasible to have productive blueberry, Juneberry or Saskatoon bushes. I would like to plant three or four bushes, but I am not sure it would be worth the trouble. (Garrison, N.D.)

A: You can plant Juneberry or Saskatoon bushes in your area, but not blueberry bushes. The Juneberry is considered the poor man’s blueberry and is very productive in North Dakota and Canada.


Q: I have a Haralson apple tree in my backyard. Several years ago, I was told that Ortho Home Orchard Spray was effective in controlling apple maggots. I found that it worked very well. The past two years, I have been unable to purchase this spray in my area. Do you know where it is available? If it is no longer available, can you recommend a substitute? For the past two years, my apple crop has been ruined by apple maggots. Thanks for any advice you can provide. (Moorhead)

A: I don’t know why the product would be taken off the market. Look for something that specifically controls the maggot, such as Methoxychlor, Captan or Malathion. This is pretty much the same formulation also found in a product known as Bonide Fruit Tree Spray Concentrate.


Q: I planted some grapevines that are doing very well. Today, I noticed something white on one of the vines. I want to know if it is something that occurs naturally with grapevines or if it is a disease that needs treatment. If so, what should it be treated with? (Danville, Va.)

A: From what I can determine, this looks like salt exudate on the vine. I have to advise you to examine it closely with a penknife to see if it scrapes off and has a salty, gritty feel to it. If it is sticky and mushy, then it is scale and needs to be controlled. Normally, scale insects are controlled when the plant is dormant by using a dormant oil spray.

Since the grape is an edible crop, I cannot recommend anything that would be safe for you to use at this time. Since your vine is small and the area of concern is limited, I suggest that you visit a local garden store and purchase what is known as Superior Oil to be applied using a paintbrush on just that area where the infestation is visible. Do not spray it on the entire vine at this time. Handling it this way usually will stop this pest immediately.

Monitor the plant through the summer and reapply the oil on infested areas. Next spring, check your vine before it leafs out. If the scale has returned, you can spray the entire vine at that time.


Q: Ninety percent or more of my apricots get a blackish rot on the flesh. Some have the rot entirely around the pit, while others have it part way and a few of the fruit do not have it at all. We average about 25 inches of rain per year with a typical drop in rain frequency during the latter half of July and all of August.

Also, some of the infested fruit has one or more earwigs that have taken up residence between the pit and the unaffected part of the fruit. I don’t know if the earwigs are causing the problem or if they are just taking advantage of a crack in the fruit near the stem as an entry point. Is this problem brown rot or something else? How can I control this problem? Should I avoid watering the areas around the tree roots or is it a good practice to water during dry spells? (Wisconsin)

A: I don’t know exactly what this malady is that you describe. However, I do know that earwigs are just opportunists feeding on the decaying fruit and surrounding flesh. You need to find a spray on the market that contains either Captan or Ferbam as the active ingredients. Bonide has such a product and so does Ortho, supposedly. They would be termed fruit tree sprays or orchard sprays.

With most insect and disease problems, sanitation is one of the major keys to control. Remove all of the old or mummified fruit from the tree and pick up all the fallen fruit under the tree. Also, keep the area under the tree canopy free of leaf litter. If you can locate one of these products at your local garden store, be sure to follow the label directions for the proper timing of the applications.


Q: Voles have eaten our new sod. What is the best way to rid our yard of these pests, and what is the best way to get the grass to recover? I raked away all the piles of dead grass. We would appreciate any advice you can give as we had such a nice yard last fall, and they have really destroyed it. (Harwood, N.D.)

A: The voles will disappear now that the snow is history. Predatory birds get to them and they also head for higher grass so they can hide. Normal human activity, such as what you just did with your raking, will keep them out of your yard. The grass eventually will recover. Come this time in June, you will not be able to tell where they had made their routes across your yard.

Kentucky bluegrass has a big advantage going for it in these circumstances because it has rhizomatous growth. These are underground stems that will recolonize the damaged areas. If it will make you feel a little better, you can get some Kentucky bluegrass seed and sprinkle it over the areas you just raked. Once the grass greens up, you can give it a shot of lawn fertilizer using a light setting to encourage some faster and thicker growth.


Q: I received a hibiscus in the mail that looked great. I planted it in a Miracle-Gro and perlite mixed soil. I watered it, but a couple of hours later it was wilted. I am wondering if it is from the shock of shipping and planting.

Should I let it be for a couple of days or is there something else that I can or should do? The other two plants that I received in the same package look good.

Any advice you could offer would be great. (e-mail reference)

A: Very likely the hibiscus got a little cooked during shipping. Give it a week to 10 days to see if it perks up. If it doesn’t, get a refund or replacement. In the meantime, don’t overdo the treatment of the plant.


Q: I planted what I thought was an autumn blaze maple several years ago. The tree has done great. However, a friend of mine who works at a nursery said the tree is a silver maple, not an autumn blaze maple. He said in 10 years’ time the tree will have roots protruding from the ground, making it difficult to mow.

We also planned on having a patio close to it, which won’t work if we have this root problem. The grass also will have a difficult time growing. He suggests I cut it down now before it becomes a problem. What are your thoughts on this? How can I tell which tree I really have? (e-mail reference)

A: Don’t cut the tree down based on a friend’s advice. Get help from a tree expert such as an International Society of Arboriculture certified arborist or send me a couple of photos of the tree in question. You just might have a silver maple that will do fine with a little selective pruning by an ISA certified arborist. There are some fantastic cultivars of silver maple that are worth keeping.

Identifying what tree it is should be straightforward because the autumn blaze is a cultivar of red maple that has distinctly different foliage characteristics than a silver maple.


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 ronald.smith@ndsu.edu.

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