Column
Ornamental Pear Trees, Mushrooms and Toadstools in the Lawn, and Rhubarb Reminders
By John Fulton
 

[July 15, 2014]  Ornamental Pear Trees -When you bought your ornamental pear tree, you probably thought it was a sterile tree (having no fruit). You were right at the time, but some things have changed. The original Bradford pear tree was sterile. It is actually a member of the Callery pear group. Due to many of the trees breaking at the graft, new varieties of the sterile, ornamental pear were introduced from the Callery group. The problem was, these different varieties cross pollinate. This means fruit forms on the formerly sterile pear tree. This feature has lead to the pear trees as being classified as invasive by many municipalities. Don’t fret though – Kentucky bluegrass and some others are also on those lists!

These pear trees have many beneficial aspects such as spring blooming, shape, relatively free of pest damage, and fall foliage color turning to red. Also the shape is great, but that shape also leads to weak branch angles causing breakage in storms. Another down-side to the Callery pear is their relatively short life, with decline often setting in between 20 and 30 years of age. There is also the fire blight issue we’ve had the past several years. I’m just pointing out the pluses and minuses of the tree, rather than passing any judgment. If you are in the process of selecting or replacing a tree, you might check out the Extension website at http://urbanext.illinois.edu/treeselector/ for information on trees.

 

Mushrooms and Toadstools in the Lawn

The symptoms of “fairy rings” have been classic this year. Dark green grass in rings that looks like a target pattern is a symptom of fairy rings. Fairy rings are visible now. Fairy rings are caused by a fungus that is in the soil. Actually there are about 50 fungi that can cause fairy rings. These fungi feed on decaying organic matter such as large roots from trees that were in the area, or from buried lumber. The dark green circle part of the equation comes from extra nitrogen that becomes available as the organic matter is broken down by the fungus. There is also a portion of dead grass in the center of the green streaks this year. It will fill in eventually.

Some prevention will help keep the problem from occurring. Simply removing stumps and large roots, and not burying lumber help prevent this type of problem. As for a cure, fungicide drenches have been successful on a very limited basis. Removal of the fungus usually involves simply mowing it off when you mow the lawn, or breaking it off with a garden rake and removing. One option to mask the symptoms of the dark rings is to fertilize the surrounding grass with a high-nitrogen fertilizer to make that grass green also.

 Rhubarb Reminders

As we are in the heat of the summer, here are a few reminders about rhubarb. The first year of establishment, you shouldn’t harvest at all. The second year you can have one or two weeks of harvest. After the second year, you can harvest eight to ten weeks. Pull the stalks, and don’t remove more than a third at any one time. The old adage of “don’t harvest in any month with an “r” in it is also good advice.

The appearance of seedstalks is a common problem. This tends to happen with cheaper plants grown from seed, overcrowding, plants that have begun declining and need to be divided and re-planted, or plants suffering from low fertility. When seedstalks do appear, simply cut them off at the base of the plant. The production of seedstalks tends to make the leaves and petioles smaller.

[By JOHN FULTON, COUNTY EXTENSION DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]