Difficult-To-Control Summer Weeds
Weeds that appear in hot summer weather are some of the toughest to control. They germinate when your lawn is under stress from heat, humidity and drought and thrive under these conditions. Some summer weeds are grass like and are not susceptible to ‘normal’ weed control measures. Here are some of the weeds you will be seeing during these hot summer months.
If a bright, yellow-green, grass-like weed is detracting from your lawn’s beauty, there’s a good chance that you’re dealing with nutsedge. Nutsedge is a yellow-green warm season perennial. It has upright, grass-like leaves with a glossy upper surface and dull lower surface that emerge from the base of the plant. The leaves are 1/8 to 1/2 inch wide, up to 3 feet long, and have parallel veins with a prominent midvein. Its flat topped, burr-like flowers occur July to September and are affixed to the end of a stout triangular stem. It grows in all soil types, especially moist ones, but does not tolerate shade.
Nutsedge is a perennial weed that is hard to eliminate, mainly because it reproduces itself from tubers beneath the soil. If you hand-pull nutsedge, the tuber is usually left behind and will regerminate. Nutsedge grows quickly in low, wet soil. Left unchecked, it will grow as tall as 2-3 feet! Pro-Lawn-Plus’s 5 Treatment program includes a summer weed spray, that helps control nutsedge. But in lawns with an abundance of nutsedge, it is usually necessary to add one or two supplemental treatments.
Dallisgrass is a light green warm season perennial. It spreads upright forming clumps with leaves that are about 1/2 inch wide. It germinates in 60 to 65 degree soils, and although it thrives in the hot and humid south, it can be found all the way up to Maryland. The best way to remove this plant is by pulling out the clumps with your hands or a small garden tool since no herbicide is currently labeled to selectively control it.
Spotted Spurge is a summer annual that produces seeds in 60 to 90 degrees Fahrenheit. From a central taproot, it grows a flat, extensively-branched mat up to 2 feet in diameter. The stems leak a milky sap when broken. Its leaves are small, oval and up to 3/5 inch long. They can be purple spotted and hairy. Flowers occur June to October and are small and cup shaped. It is found in thin, drought-stressed soil in hot climates and closely mowed grass. This weed is resistant to many weed control products. To minimize Spotted Spurge, water deeply,, fertilize in autumn and avoid close mowing.
For information about these and other weeds, visit the Difficult to control weeds section of our website .
Mark Schlossberg is the President of ProLawnPlus in Baltimore, MD. He graduated from the University of Maryland in 1977 with a B.S. in agronomy. He is the President of the Maryland Association of Green Industries, and past president of the Maryland Turfgrass Council.