Advertise in Print | Subscriptions
Published May 14, 2010, 12:00 AM

Getting rid of fairy rings requires patience

Q: We noticed rings in our yard as the grass started to grow, so I checked the Extension website to find out what the problem could be.

By: Don Kinzler, INFORUM

Q: We noticed rings in our yard as the grass started to grow, so I checked the Extension website to find out what the problem could be. I’m pretty sure our lawn has fairy ring problems because they look very much like the photos on the website. I counted at least 15 rings in our yard, so digging them out is not possible. (e-mail reference)

A: You can mitigate the problem by following a few steps. Core aerate the entire lawn area, but go over the affected areas twice. Maintain optimal fertility of your turfgrass with regular fertilizations throughout the season. The applications should be made at or around Memorial Day weekend, July Fourth holiday and around Labor Day weekend. Maintain a mowing height of 3 inches or more and allow the clippings to drop. If the response seems to be slow, spray the area with a wetting agent that is available at most garden center outlets.

Sometimes the fairy rings become hydrophobic, which contributes to the unattractiveness of the problem. Given time, this will become a thing of the past, so just be patient.


Q: I have an old silver willow tree in my backyard. Someone told my husband that the roots of the tree are going to plug our septic field and the weeping tile around our house. The tree trunk is about 50 feet from the house and 60 feet from the septic field. My husband has noticed hairlike roots growing into our well casing where there are holes for pipes. Does this mean my beautiful tree has to go? What is the best way to do it so that we don’t have little trees popping up? (e-mail reference)

A: It probably should go based on what you have told me. Have it removed after it leafs out this spring. That way, most of the stored carbohydrates from the previous year have been expended to generate new growth. Cutting it down at that stage will result in very few sprouts coming up from the roots remaining in the ground. Sprouts that do come up can be treated like weeds and be sprayed with a good broadleaf herbicide.


Q: Our tree has walnut-sized growths around three small branches. They are very hard and look like wood when I cut into them. Do I cut them off?

(e-mail reference)

A: These growths are some kind of gall, which are usually not harmful to the tree. You can remove them with a pruner or just ignore them.


Q: I have noticed several areas on my lawn that look like tightly woven spider webs. They are solid white and are all over the grass. Each one is 3 to 4 inches in diameter. Has anyone else had this? Is this problem anything to be concerned about, or should I leave it alone and mow when the grass is ready? (Ransom County, N.D.)

A: As ugly as it looks, you have nothing to worry about. This year, you have lots of company with people who have this problem. This is gray snow mold, which is a fungal disease that gets started in turfgrass that is under snow. To aid in the healing and recovery, take a leaf rake and rake the affected areas. This will allow the area to dry and the grass to grow faster. If you want to feel even better about getting it to recover quickly, get some good-quality grass seed and sprinkle it in these areas. By this time in June, you’ll never know you had this problem.


Q: We have a Persian lilac tree. Last winter, the weight of the snow on it cracked the crown in half. Should I saw off the entire crown and let it grow back, or should I saw off the badly damaged part of the crown and leave it go at that? (Richardton, N.D.)

A: With the snow gone, a lot is revealed. Without being able to come out and see your tree, you would do it no harm by cutting it back completely and letting the new growth fill everything in again. You’ll lose the flowers for this year, but that is no big deal in the grand scheme of things.


Q: My yard is wet and has little bumps all over it. The bumps are little mounds of black dirt. What little creature is causing this, and how do I get rid of the problem? Is it night crawlers pushing up the dirt? (Valley City, N.D.)

A: Yes, you have night crawlers doing their spring activity. They are most active now because the soil is so saturated, so they are attempting to get air.

You can take two approaches to control the problem. Apply a granular grub insecticide following the label directions. This will kill about one-third of the night crawlers. Don’t worry about this problem because every lawn has grubs.

You also can get a ballast roller and fill it about halfway with water and go over the lawn while it is still soft. This will flatten out the mounds and also provide a small kill of the most vulnerable grubs. Most importantly, you will be able to mow your lawn without twisting an ankle.


Q: I have two lilac bushes we want to move. One is about 5 feet tall, while the other is closer to 8 feet tall. How do I know how deep to dig around the roots?

The larger one looks more like a tree. Is there a best time of year to transplant? (e-mail reference)

A: In reality, it all boils down to how much of a rootball you can handle. The more the better for the lilac, but it is not worth it if your back gives out in the effort. With the small shrub, the ball size should be at least 24 inches in diameter and also that deep if possible. For the taller shrub, the ball size should be 36 inches in diameter and about 30 inches deep. The best time to move these plants is while they are dormant in the early spring. Depending on where you live, you can do it in the fall after defoliation, but this assumes you have mild winters.


Q: This winter, we had several big snowstorms. As a result, the bottom areas of my arborvitaes have turned brown and thinned out. Is there anything I can do to restore new growth and prevent this problem? (Long Island, N.Y.)

A: If there is any trace of green foliage remaining in these areas, there is a good chance these damaged areas will recover. This spring, carefully cut out all the dead tissue but leave anything that is green. Before new growth begins in the spring, give the plants a shot of Miracle-Gro fertilizer and hope for the best. When you have a winter like this with so much snow, it is difficult to keep damage from occurring. Let’s hope that a snowy winter like this one doesn’t come back again within our lifetime.


Q: I have two red maples that are about 2 years old. They budded earlier this spring, but no leaves have come out. I was wondering how you can tell if the tree is dead or are they sometimes late bloomers? (e-mail reference)

A: Without knowing where you live, but assuming it is nowhere near North Dakota, all I can guess is that they were “teased” out of dormancy with above-average warm weather, then halted with a return to perhaps more seasonal, cooler weather. If this is not the case, then it probably is an indication they are dead. Give them until the end of April. If leafing doesn’t occur, consider the fact that they need to be replaced. They may have been planted too deeply, which is the most common cause of newly planted tree loss. Overwatering is the other big problem.


Q: My red twig dogwoods are being attacked by what I think is some type of disease that will sever a large branch or new shoot of growth at the base of where it is branching off. It is devastating the plants. I say disease because I see no type of insect at all. I have taken samples to local nurseries, but they are of no help. The plants look great now and are putting out wonderful new growth. However, as in the past, I am almost certain they will be affected soon by the same problem. What is doing all this damage? (e-mail reference)

A: From your description, it could be dogwood borer problems. This is a clear-wing moth that lays its eggs at the base of the tree. The hatchling grubs proceed to feed, causing the stem to collapse. This could be controlled with a topical spray, such as Lindane, or a systemic, such as Bayer Advanced Tree and Shrub Insect Control. Pathogens usually leave some kind of evidence behind, such as cankers, rot or leaf spot. If you are convinced that it couldn’t be an insect, then I’d suspect something else, such as voles that like to nibble at the base of the plant.


Q: I’ve been thinking of building a cold-frame greenhouse (unheated). I start vegetables and flowers inside under lights but was thinking I could move them outdoors sooner in the spring to harden off if I had a cold frame. I also think the plants would develop better with real sunlight. How much will a cold frame protect plants? In other words, how cold can it get before the plants will die? Am I better off keeping the plants inside under longer light periods than using natural light? Are cold frames any advantage in this climate? (Fargo)

A: Cold frames can be used in our area very effectively. However, don’t try to push the limits. Cold frames will protect from frosty nights, but not for long, low-temperature periods, especially sensitive plants such as tomatoes, peppers and egg plant. Cabbage, broccoli and lettuce might be able to tolerate a long period of cold.

What some folks have done when extended cold threatens is have an incandescent light or two tucked into the cold frame to keep it from getting too cold inside to do damage. Basically, if the temperature is going to nose-dive down into the mid- to upper 20s for the night and it is preceded by the daytime being warm and sunny, there is enough residual heat within to keep the plants from being damaged.

Another trick we used if we knew the plants in the cold frame would be history the next morning if you didn’t do something drastic was to take some burlap sacks and get them soaked in water and lay them over the cold frame at sundown. When the sacks froze, they acted as an insulator for the plants in the cold frame.

As far as the lights go, natural light quality and length always trumps what we provide indoors. The seedlings adjust their growth to what they are given, which is usually better.


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.

Tags: