Cyperus esculentus and Cyperus rotundus
Also known as Nutsedge, purple or yellow nutgrass
Nutgrasses are perennial sedges imported from Eurasia, which spread by seeds, nutlets, and creeping tendrils. Considered an invasive, they tend to appear in wet, anaerobic soils. Nutgrasses are easily identifiable by their narrow, grass-like leaves which can be green to yellow-green. The leaves erupt erect from a center point then turn outward in 3 directions. Seed heads are yellow-brown. Nutgrass dies back in the fall but leaves an underground tuber which overwinters in the soil. A single nutgrass tuber can produce 146 new tubers in 14 weeks the following spring in an area 6 feet in diameter around the original tuber.
Regardless of what your landscape guy tells you, there is no reliable and good chemical control for nutsedge. There are two commonly used products. One doesn’t work at all. Both will severely damage trees and hedges if used repeatedly.
Organic control is more common sense. Keep the nutgrass mown back and prevent the seed heads from forming. Pull the entire plant when you find it, trying to remove all the underground tubers as possible. Some believe that any part you leave underground will regenerate and come back. Spot spraying with a 20% vinegar solution also works but may require multiple applications to the same plant. Large clumps will often succumb to drenching with liquid molasses mixed at a ½ cup per gallon of water.
Healthy Soil is the Key
The real solution is to maintain your soil in as healthy condition as possible. Nutsedge grows primarily in wet, anaerobic soils. The easiest solution to nutgrass is to be sure that you are watering only when your turf needs watering. Automatic sprinkler systems are the leading cause of nutgrass infestation. They are usually set to water too often and too much, resulting in wet, oxygen-deprived soil, perfect for nutgrass.
Turn off that automatic controller and start managing your water applications. Water only when needed and only in areas that need moisture. Let the soil dry out between watering. In many instances, once the soil is dry, the nutgrass will fade away and become a bad memory.
There for a reason
Remember that weeds appear for a reason. They are telling you that something is wrong with the soil or with your turf. Healthy soil is highly resistant to weeds, and a healthy turf will choke out most weeds. You will still get the occasional weed but no infestations. Figure out why the weeds are appearing, and it is easier to figure out how to control them organically.
Links and Resources
For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening.
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