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

June 24, 1999

Ron Smith, Extension Horticulturist
North Dakota State University

Q: I have a Crimson King maple tree that I planted in March, and the leaves are getting a brownish color covering most of the leaf. Could you tell me what is wrong with it? (Lake City, S.D.)

A: Unfortunately, our prairie environment in the Dakotas is not kind to Crimson King maples—a cultivar of Norway maple. Our alkaline soil conditions and weather extremes make these poor choices to use in the landscape.

The root system—the entire tree, in fact—is showing site incompatibility. There is no recommendation I can make that will improve the situation. I suggest removing the tree and replacing it with something else. Sorry about the bad news.

Q: Could you please tell me what the lumps and brown spots are on my cotoneasters and what to do with them? (Glyndon, Minn.)

A: The cotoneaster, I suspect, was hit with contact pesticide, perhaps Malathion a on hot day, or the water table is high enough that it is killing off some of the roots due to anaerobic (oxygen-less) conditions. These are just guesses, but overall I don't believe you have anything to worry about as the new growth on your sample is looking very healthy.

Q: How can I get rid of a weed that is about 1½ inches high and has small blue flowers on the plant? (Erie, N.D.)

A: Your weed is ground ivy—Glechoma hederaceae. It's a very tough perennial to get rid of, but it can be done with repeat applications of a product known as Trimec. Be sure to follow label instructions.

Q: What can I spray around my house to get rid of mice? (Buchanan, N.D.)

A: It is not a spray, but ground-up corncobs infused with a variety of herbal extracts formed into a "brick." The strong herbal odors drive them away but do no harm and smell pleasant to us humans. The contact to make is Kari Warberg at Crane Creek Gardens in New Town, N.D. Her toll-free telephone number is 1-800-583-2921. She could answer questions about this product.

Q: I have two pear trees that are about 15 years old. They only blossomed one year and produced only a few small pears. Can you tell me why they are not producing and how to get them to produce? (Gettysburg, S.D.)

A: Fifteen years and literally no fruit? I'm surprised you haven't converted them to firewood by now! Pears are generally not a good bet for the Dakota prairies—the soil is too alkaline, and they are subject to fireblight. In addition, as you pointed out, they bear poorly.

Purple pear leaves are often associated with phosphorus deficiency brought on by a tie-up with excess calcium in the soil when the pH is excessively high. This is also another reason for poor fruit set.

You won't like my advice, but I followed it myself after being unsuccessful at growing productive pears at my home. Get rid of the pear trees, and plant an apple tree!

Q: We transplanted a tree that we think is an ash tree. Can you tell me why it has bumps on most of its leaves? I am also wondering if I was correct when I moved my spruce tree out from under this ash tree. (Montrose, S.D.)

A: The leaf samples you sent in were from a silver maple, not an ash tree. The bumps are actually tissue galls, caused by feeding in the earlier part of the season by very small mites. Their damage is cosmetic, not lethal. No control is necessary or practical.

You were right in moving the spruce from under the shade of this maple tree. Spruce—most evergreens, in fact—don't relish shade. Your small spruce should thrive in a fully sunny location.

###

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