Home Gardening

Weed ID important for proper control
The Coast Gardener Newspaper and Web Column - February 9, 2002

As promised last week, I will further explain weed control strategies for your home lawn. Do you recall the last sentence from my previous column? I cannot say too many times that a relatively weed free lawn starts with a healthy turf.

Even with proper liming, fertilization and watering practices, your lawn can start to lose the battle against some weeds. Weeds such as Florida betony (rattlesnakeweed), torpedograss, Virginia buttonweed, and pennywort (dollarweed) are aggressive enough that physical removal by hand is not the best way to achieve adequate control.

Herbicide usage is necessary to keep these and other problem weeds from taking over your lawn and competing with important nutrients that are required for proper growth. I explained last week about selective, nonselective, preemergence and postemergence herbicides. Understanding such terminology is an important step to achieving positive results when managing weed populations.

Another important step is to correctly identify the weed that is giving you headaches and causing your blood pressure to rise. Broadleaf weeds, grassy weeds and sedges are three different classes of weeds that are selectively controlled in different ways. Broadleaf weeds and grassy weeds are easy to tell apart, but many gardeners ask, "What is the difference between a sedge and a grassy weed?" Simply stated, a sedge will have a triangle-shaped or three-sided stem and a grassy weed will not. That is the easiest way to tell grassy weeds and sedges apart. Weeds such as purple and yellow nutsedge can be a real challenge to control.

Not all herbicides kill all weeds. It is for this reason that weed identification is a critical step in controlling certain weeds. This is not to say that you must identify every weed in your lawn. Herbicides kill groups of weeds in many cases; however, you may notice a few weeds that are not killed. These are the weeds you must identify, because there is likely a control recommendation out there that requires a more targeted approach.

Be extremely careful when selecting herbicides. Don't purchase anything without prior considerations. You must know the type of turf in your lawn before using any herbicide. St. Augustinegrass, centipedegrass and bermudagrass have separate requirements. If you are not careful, you can severely damage or kill your turf if you use the wrong herbicide.

The label is a very important document to read on any pesticide. A herbicide label describes application rates, weeds that are controlled, what type(s) of turf you can apply it to, and any precautions you need to take for yourself or other plant material. If the herbicide is not labeled for a particular use, you are breaking the law if you misuse it. For example, some herbicides meant for home lawn use will injure desirable plants such as trees, shrubs, flowers and vegetables. Some simply are not cleared for application in vegetable gardens or shrub beds. Read the label carefully before you decide.

Weed control is an essential part of good management practices for home lawns. I encourage you to pick up a copy of publication 1322 "Establish and Manage Your Home Lawn" at you local county Extension Service office. You may also visit our web site at MSUcares.com and view the publication as well.

These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.