NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

June 6, 1999

Ron Smith, Extension Horticulturist
North Dakota State University

Q: Every year I have a large percentage of my lawn that is damaged. I understand it is due to the ground still being unthawed and covered by snow. Are some varieties of grass more susceptible? (Fargo, ND., e-mail)

A: All species of cool-season grasses are susceptible. It depends on cultural practices to the degree of snow mold infection that occurs.

1. Avoid late-fall applications of fertilizers high in nitrogen, which cause the grass to go into winter in a soft, lush condition.

2. Make the last mowing about a half-inch shorter than the height you kept it at during the growing season. This should take place around Columbus Day or later.

3. Stop irrigating by Oct. 1 (or sooner) to get the grass to enter the winter in a more dormant state.

4. Try to improve drainage in that location via core aeration during the growing season. Try to keep the thatch thickness to less than a half inch. If it reaches that thickness, power rake and /or core aerate.

It might also mean the need to bring in some topsoil to help improve the surface drainage of the area. I have a chronic problem on the south end of the football practice fields that I care for on the campus. It is the lowest area, poorly drained, and is always affected by snow mold. I simply aerate, power rake, and over seed for another season. Some day when time permits, I'll bring in some topsoil to raise the area to help improve surface drainage.

Q: We have one Canada red cherry and two plum trees. How do we watch for black knot? We have never heard of it. (Horace, ND., e-mail)

A: Be thankful you have never heard of it! If it should ever get started on your trees, you will know it by the following characteristics:

1. Soft greenish growth about this time of year that completely or partially girdles the branches of the tree. These galls develop into black, corky growths that resemble burnt marsh-mallows on a stick.

2. The branches where this gall appears will be either stunted and partially foliated, or completely dead.

3. The disease is a fungus that spreads and is especially active during wet weather in the spring. It has been a good year for the fungus!

Control is by selectively pruning out the infected branches during the fall and late winter. Be sure to cut at least 4 to 6 inches below the area of swelling on the branch. Spray the trees with a fungicide containing benomyl next spring before bud break. Respray two more times at 10-day intervals.

Q: I want to convert part of my lawn into prairie with little bluestem, grama, and buffalograss. The yard on the south side and the front of the house will be used more and will be mowed on a regular basis. These areas will eventually be watered by a sprinkler system. What grass seed would you recommend for these areas? (Bismarck, ND., e-mail)

A: I would suggest a grass seed mix that would have some South Dakota common, Kenblue, or Park Kentucky bluegrass as a major part of the mix. These are tough grasses that will stand benign neglect and still look good. Another one if you can find it is Ram I Kentucky bluegrass. This would be good for the areas you eventually plan to irrigate with a sprinkler system. It has the ability to withstand low maintenance inputs or a lot of TLC—whatever—and still look good.

Q: My question for you is how can grass/weeds be kept out of strawberries (without physically pulling)? Is there something that can be sprinkled/sprayed on without damaging the strawberries? If so, what is it and where can I buy it? (Pukwana, S.D., e-mail)

A: The materials that are cleared for strawberries are as follows: Dacthal, Devrinol, Forumla 40, Poast and Prisim.

Q: I am having a hard time growing grass—period. I have tried Kentucky bluegrass with no luck! I have lots of sunlight. What should I do? (Louisville, Ky., e-mail)

A: So the bluegrass state won't grow Kentucky bluegrass? Well, try a transition zone grass like Arid or Bonanza tall fescue. Your part of Kentucky is mild enough that this species should establish beautifully.

You want to get the lawn started as soon as possible to allow the crowns to mature before going into winter. Sow thickly, about six to eight pounds per 1,000 square feet, and you should have a beautiful, durable lawn in no time. Keep it mowed at 3 inches and fertilized twice a year (spring and fall) and you should have a very attractive lawn.

Q: I have been told to use Sevin to force some apples to drop. I have quite a number of trees and I would like them to produce every year. At what rate do I mix the Sevin? (Elbow Lake, Minn., e-mail)

A: Sevin is used at a rate of 3 tablespoons per gallon of water two to three weeks after bloom. You might want to look for two other products that would do the same thing but not have an adverse effect on predatory or pollinating insects: Fruitone N and App-L-Set. These are growth regulators, instead of insecticides, that need to be applied at full bloom to be effective. Another one that can be used is Florel Fruit Eliminator, which gives off ethylene gas, another growth regulator. All of these will cause fruit drop at the embryo sate.

Q: For the first two or three years my Tristar strawberries did very well, bearing fruit from spring until fall. For the past couple of years, they have blossomed and the fruit appears, but withers before maturing. The plants have also thinned out a lot. The local nursery told me to use Bonide Mite and Insect Spray with Kelthane. After reading the cautions on the bottle I'm hesitant to use it. What do you advise? (Moorhead, Minn., e-mail)

A: These day-neutral strawberry plants lose their productivity capacity after about a year, if they should survive our winter at all. Be happy you got what you did with them! We normally recommend that growers should not expect any more than a single season from the day-neutrals, and encourage them to plant some June-bearing cultivars like Honeoye, Redchief, and Gloosecap.

So spray no more, it won't do any good. Simply replace them with something more productive.

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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.

Source: Ron Smith (701) 231-8161 ronsmith@ndsuext.nodak.edu

Editor: Dean Hulse (701) 231-6136