Lawn Weeds of Summer
By Paul Schnare
Monday, July 21, 2003
Although many different weeds thrive in your lawn during the summer, other than crabgrass, the weeds that get the most attention are clover, lespedeza, nimblewill, and nutsedge. With a little effort these weeds can be controlled, and you can get the “golf course” look back in your lawn.
Most people know what clover is. You spent time looking for four-leaved clover when you were a kid. Although I occasionally see clover in any lawn, it shows up in lawns that are usually undernourished. It also spreads rapidly during wet springs.
The presence of clover can be considered a good thing. Clover has the unique ability to pull nitrogen out of the air and place it in soil. In effect it is natures way of fertilizing your lawn. On the other hand, the white flowers of clover ruin the even greenness of a lawn. Its dense spreading growth habit tends to crowd out desired grasses.
If you want to rid your lawn of clover apply trimec at the suggested label rate two times about a week apart. The first application injures the tiny hairs that cover the cloverleaf. Upon the second application, the herbicide easily moves into the plant through the leaves and kills the plant.
Lespedeza is a kissing cousin of clover. It has smaller leaves, yellow flowers, and shows up readily in zoysia lawns. It, like clover, can be controlled with trimec. But because lespedeza has woody stems, you may need to make more than two applications.
Nutsedge, or as a lot of people call it, “watergrass”, makes its presence known the day after your mow your lawn. Nutsedge grows so fast that it is usually two to three inches taller than the rest of your lawn by the next day.
Nutsedge is called water grass because it usually shows up in low moist areas in your lawn. This light yellow looking “grass” has a very angled blade. If the blades are allowed to grow to maturity, a seedpod develops at the top of plant. You can also find small nutlets among roots of the mature plant if you dig up the root system.
The chemical of choice to eliminate nutsedge is basagran. Follow label directions when making the applications. Under warm, dry conditions basagran can “burn” your desirable grass. To eliminate this problem, water your lawn one day, make the basagran application the next day, and then water your lawn again the following day. This procedure usually eliminates any burn potential.
Another pesky summer weed that often shows up in old shady lawns is nimblewill. This weed, often mistaken for Bermuda grass, spreads by its root system. The only way to control this common weed is to apply glyphosate at labeled rates. Glyphosate is a total vegetation herbicide with very little residual. Later in the summer you will need to reseed the areas that you treated with glyphosate.