Snow, weeds and nuisance fruit

By John Fulton

[March 30, 2009]  We are now on the books with the first snow of spring. Two to 4 inches of the white stuff, but at least it didn't last long. We really won't have any ill effects to plants from the snow; quite the contrary, as it provided an insulating blanket for everything. Grass and early garden plants look better after the snow than two days ago. Of course we can do without any more for this season. The main problem is the moisture accompanying the storm. Soil will be too wet to work for several days now, and this fact can put us a little behind on the gardening calendar. Don't worry, unless the trend is prolonged. Heat units accelerate as we approach the summer months, and many crops catch up quickly.

Winter annual weeds

Each year, the winter annual weeds chickweed and henbit run No. 1 and 2 in the early spring. This year is seems like henbit is running slightly ahead. Winter annual weeds can actually germinate in the fall, carry through the winter, then get going very early in the spring. They also are done by the heat of the summer, leaving seed to germinate again later in the fall.

Right now chickweed stands out in yards because it is quite abundant and has a lighter green color than grass and most other weeds. I can't begin to tell you how to identify it; it gets even harder when there is common chickweed and mouse-ear chickweed.

Henbit is easier to identify since it has purple flowers and smells like mint.

As for control, that gets a bit easier. The straight 2,4-D that is used on dandelions seems to act like a fertilizer for chickweed and other problem weeds. Combinations that contain 2,4-D, MCPP and dicamba are rated very effective on chickweed, henbit, red sorrel, purslane, white clover and others. Just remember the control time for most broadleaf weeds is early May. These combinations are sold under several different trade names. You can find these at most hardware, discount, and lawn and garden stores. Just check the label under active ingredients and check for two long chemical names and dicamba. You can also check to see that it says it will control chickweed and henbit. This group of chemicals is effective in the 50-degree range and up.

As with any chemical control, read and follow label instructions very carefully. You should be aware of some cautions on these product labels concerning injury to sensitive plants. This is because dicamba can drift as a vapor for a few weeks after you apply it, if the weather gets hot and sunny.

Nuisance fruit prevention

One of the main things to discuss today is the removal of nuisance fruit. You may be thinking about those apples or peaches, but really the nuisance fruit category includes things that are much more a nuisance, like sweet gum balls, maple seeds and crab apples.

There are several products available to eliminate nuisance fruit. The most common is ethephon, and it is used as a foliar spray to reduce or eliminate undesirable fruit or seeds. A couple of the trade names are Florel and Ethrel. The product is effective at eliminating much of the fruit without affecting leaf growth and color, and it does not harm other plants that get some spray drift on them. It also does not affect the actual flowering of the treated trees.

With ethephon, the key is in the timing. The application must be made during flowering but before the fruit set in. For most flowering trees there is a 10- to 14-day window of opportunity. Sweet gums are a little tricky since there are no showy flowers involved, so effective sprays should occur just as new leaves begin to emerge. Sprays should leave leaves wet, but not to the point of dripping. Good coverage of the tree is needed, so keep in mind the size of the tree when you are weighing this option. There are injectable products available, but they must be applied by a professional. The injectable products have not been as effective as the sprays.

This product is a growth regulator that naturally occurs. Its natural production is stimulated by stress, so make sure you aren't treating a tree that is under stress from drought, high temperatures, diseases or other environmental stresses. Treating stressed trees can cause severe injury to the plant, such as leaf loss or scorching.

[By JOHN FULTON, University of Illinois Extension, Logan County]