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Published September 24, 2010, 12:00 AM

Elm tree sap likely culprit for grass woes

Q: My neighbor has a bare spot in her yard to the north of a large elm tree. I have watched it this summer and noticed that I have the same thing forming near my elm tree. She also is now getting a similar spot on the opposite side of her tree. Is it something to do with the tree roots? Any suggestions are welcome.

By: Don Kinzler, INFORUM

Q: My neighbor has a bare spot in her yard to the north of a large elm tree. I have watched it this summer and noticed that I have the same thing forming near my elm tree. She also is now getting a similar spot on the opposite side of her tree. Is it something to do with the tree roots? Any suggestions are welcome. (Fargo)

A: Look up into the canopy of the trees right above the dead spot. I would guess there is some sap dripping down that is killing the grass. This is a common problem. Other than cutting the respective trees down or at least pruning the offending branches, there is no cure for this problem.


Q: I hope you can give me some advice about a birch tree. I bought my house two years ago, and it has a large, topped birch tree near the house. The tree was topped at about 20 feet. It has grown vertical spires that are quite thick. I have heard that this type of vertical growth is not attached to the main trunk very well, so they might come down during a storm. How should I maintain the tree? I am planning to have it pruned before winter. Do you have any suggestion for me? Thank you very much for your help. (e-mail reference)

A: My best advice is to look up an International Society of Arboriculture-certified arborist. Go to www.treesaregood.com/findtreeservices/FindTreeCareService.aspx to find one in your area. I cannot give you advice without seeing the tree. Even then, on-the-spot decisions need to be made as the pruning process is undertaken.


Q: I have a very old Concord grape vine. The grapes are small, hard and split open. The grapes also have a grayish exterior resembling a fungus. We have had bountiful years, but the past two years have not been good. I don’t see any insects, and I don’t fertilize. The problem may be that I live in Oregon. I wonder if the temperatures or the amount of rainfall we get are the problem. Can you give me a hand as to how to prevent this condition, assuming it’s not rainfall? Thanks for your time and help. (e-mail reference)

A: You live in grape country. I would assume that the folks in your county Extension office would be more on top of this problem than I would. I suggest going to http://extension.oregonstate.edu/locations.php to find an agent in your county who can get you hooked up with an expert. Grape vines will produce greater amounts of healthier grapes if they are tended somewhat. It appears that your vine has not been pruned for a long time. This will cause uneven ripening and overproduction of the grape clusters, and creates a microenvironment for disease development. In your case, it looks like the vine has powdery mildew.

You need to make a local contact to be able to get an accurate diagnosis.


Q: I am having problems with my daisies in one section of my garden. They seem to grow well, and the buds appear, but the flowers don’t open. I tried cutting them down in the fall, but the next year I had the same problem. (e-mail reference)

A: Flower buds not opening usually are caused by a minute insect actively feeding beneath the flower sepals or bud scales. Gladiolus thrips usually are the culprit. They are small and difficult to control. Next season, apply a systemic insecticide early on in the development of the daisies to see if that will provide some control.


Q: I am a novice spider plant grower. After reviving my dying spider plant, I was overjoyed to see it sprouting baby spider plants. I clipped the stalks off and placed them in a jar with tap water. I have not seen any root growth, and the leaves are turning brown. I moved them to an area that gets less direct sunlight because I thought the summer heat and sun were burning the leaves. However, there has been no improvement since they were moved. When I took one of the stalks out of the water, it felt as though it was dehydrated and more reedlike than anything else. Can I try to put them in soil at this point even though they are no longer attached to the mother plant? If not, do you have any suggestions?

I was really looking forward to passing along the babies to my friends. (e-mail reference)

A: I don’t know what you did incorrectly unless you are too impatient. I suggest trying to place the plants in some pasteurized and moistened potting soil. Keep the soil moist, but not soggy. Wait about six weeks before looking for roots to begin developing. If they don’t show anything by that time, then something was damaged during their removal from the mother plant. It is much easier if you can root the baby spider plants while they are attached to the mother plant. All the light they need is what normal interior lighting provides.


Q: I have a pine tree that I transplanted last fall. It has been doing great, but lately the leader and now a few around it are turning brown. Is there an issue with the tree, or is it just because fall is coming? I appreciate any feedback. (e-mail reference)

A: Pine trees do not change color in the fall. This is an indication of bark borers or something else affecting the health of your tree. If you can, examine the area closely to look for holes with frass coming from them. Definitely cut that part of the tree out if you find holes. Send a sample to your land-grant university plant diagnostic lab.


Q: I have six old prairie spire green ash trees. When is the best time to water them before winter hits? Thanks for your help. (Bismarck)

A: Between now and when the leaves drop is the best time. However, don’t keep the soil saturated. Depending on rainfall distribution and amount, give the trees a good soaking every 10 or so days. Once the leaves have dropped, you can shut off the water to the trees. With normal fall weather, they should be OK until next spring. With evergreens, keep the soil moist right up until it freezes if possible.


Q: I am writing because I saw the questions you answered about poplar trees. My in-laws have new neighbors who planted poplar trees along the property line. We believe the trees are Lombardy poplars. They planted the trees about 15 inches from the property line. Would planting a Lombardy poplar tree that close to the property line be considered unadvisable, and what should my in-laws be concerned about?

My in-laws are afraid of the potential damage to their driveway, which is less than 3 feet from the property line, and also to the foundation of their garage, which also is located 3 feet from the property line. There is a possibility of damaging the garage roof as the trees get larger and rub the roof in the wind. I greatly appreciate anything you can advise in such a situation.

(e-mail reference)

A: Lombardy poplars should not be planted at all. They have an almost unvarying history of problems with surface roots that are aggressive in growth and lifting sidewalks. Lombardy poplars produce a lot of kindling wood to pick up prior to mowing and play host to an almost endless number of insect and disease problems.

Beginning entomologists and pathologists could get a good start on launching their careers by studying what this species of poplar supports throughout its relatively short life. Being planted as close as they are to the property line gives your in-laws some valid cause to worry. However, I might contend that the trees won’t live long enough to be a serious physical problem.

If the neighbor scoffs at these warnings and refuses to remove these new plantings, your in-laws can have the somewhat vengeful satisfaction of watching them go through all the inherent problems common to this tree before they give up in frustration and tear them out.

Not trusting fate to behave in their favor, the in-laws can get some bio barrier installed between the plantings and their driveway and foundation. The barrier will keep the roots from penetrating beyond the point of installation. Root barriers often are used around golf course greens to keep the adjacent tree roots from penetrating into the greens and raising havoc with maintenance and play.


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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