Archive for Sunday, May 30, 2004

Clopyralid helps control broadleaf weeds

May 30, 2004


Summer days are best spent enjoying picnics on lush, green lawns.

However, I woke the other morning and thought it had snowed because so much of the green space was white. Upon further inspection, I realized the untimely color was caused by the blooms of Dutch white clover -- a perennial weed in most home lawns. A gardener's first response is to load the sprayer and begin spraying. But the chemicals applied can do more than kill weeds, they can contaminate the compost pile.

Here are some tips to help control the weeds and not harm the compost:

Clopyralid (clo-PEER-a-lid) is the active ingredient found in at least 28 herbicide products registered for use in Kansas. It does an excellent job of controlling broadleaf weeds in the sunflower, legume, nightshade, knotweed, and violet families. These are plants such as clover, thistles and dandelions. It is an auxin-mimicking herbicide that influences plant growth and causes unusual growth patterns like stem swelling and elongation, leaf cupping and leaf rolling. This is followed by plant yellowing, wilting and dying.

Homeowner and commercial herbicides contain the active ingredient clopyralid. These herbicides will list the active ingredient as either clopyralid; clopyralid, monoethanolamine salt; clopyralid, triethanolamine; or 3,6 dichloropicolinic acid. When purchasing weedkillers or when having weedkillers applied to the lawn by a professional, inquire about the active ingredient to determine if it is clopyralid.

Why all the fuss? The chemical is not broken down by sunlight or water. It stays in soil, water and vegetation until soil microbes can break it down. When grass clippings treated with clopyralid are added to the garden, flowerbed or compost pile, many of the plants growing in these areas will show the same symptoms as the weeds do. Clopyralid is safe for birds, aquatic animals and humans when used properly.

Read the label and determine if you are using clopyralid. If so, do not compost your grass clippings. Simply mow the grass and let the clippings fall.

For more information and a complete list of products containing clopyralid, visit the Lawrence Waste Reduction and Recycling Division at

If you must collect or compost your clippings, use the chemical triclopyr found in the herbicide Turflon Ester. But now is not the best time to use it. You will have better luck in the fall when the plants are moving food to the roots because it moves the chemical there as well. If you do decide to spray, make sure the soil is watered, temperatures are below 90 degrees and the wind is not blowing hard. As always, be sure to read and follow all label directions.

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