On the side of our garage, there is a small flower bed that was home to two azaleas. The shrubs were small and weren’t flowering well. The area they were in was not only in full sun, but it was also an area where water seemed to pool.
Adding to their struggle was the infiltration of some sort of grass that would grow around and through the poor azalea. The surrounding turfgrass is Bermuda, but this grass was different; tall and fast-growing, with glossy yellow-green leaves. It didn’t have roots similar to those of turfgrass. When pulled, it had bulbs, called tubers, under the earth.
After rescuing the azaleas to give them a home more suitable for their growth, we pulled out this pseudo-grass and put down some weed-killer. It wasn’t long before it was back, and no longer content to live in the flower bed. Sprigs were popping up in the grass surrounding the bed and had moved around the building to invade the bed there as well. We pulled everything we could see and put down a ground clear solution over the entire bed. Surely, that would put an end to it.
Nope. It came back again and was spreading through the lawn like a weed. Well, that’s because it is a weed.
Yellow nutsedge (Cyperus esculentus), commonly called nut grass, is a warm-season perennial weed with blade-like leaves that are up to a half-inch wide and can grow as tall as 3 feet. Nutsedge reproduces from the tubers under the soil, making hand-pulling only mildly effective if you only get the blade portion above the soil and leave the tuber.
It grows quickly in wet, poorly drained soil and is a particular problem in years with above average rainfall. It will produce seed heads in July through September, and each plant can produce hundreds of seeds per season.
Getting rid of this weed is difficult and will take the use a few combative measures together to get the job done. Diligent lawn care, including mowing at the ideal height, fertilizer applications and proper irrigation will help the lawn compete against the onset of nutsedge.
Lawns should be mowed to the ideal height based on the type of grass you have. For instance, if you have common bermudagrass, it should be kept to a height of approximately 2 inches. If mowed too low, it creates an ideal environment for nutsedge to grow.
If the area with nutsedge is small, you can dig at least 10 inches deep and 8 to 10 inches around the perimeter of the infested area. However, all of the soil must be removed and replaced with clean soil. Small baby tubers, called nutlets, may be undetectable, making total removal of the soil necessary to avoid having the nutsedge return.
Sedge specific herbicides can be applied to the lawn — unfortunately, a single application generally will not eradicate the weed. It may take several applications at 8-to-10-week intervals. Common herbicides used to combat nutsedge include imazaquin, bentazon and halosulfuron. Use caution when using these herbicides near bedding plants, as they may damage foliage or roots of nearby ornamental plants. It is important to use herbicides that are engineered specifically for nutsedge, as general broadleaf herbicides are ineffective.
Continued weeding, fertilization and an application of a pre-emergent in spring will also aid in eradicating nutsedge. Filling in spots that pool water and improving drainage throughout the lawn will also reduce the desired wet ground they thrive in.
It may take several seasons to completely rid your lawn of this tough weed, but it can be done. Until next week, happy gardening.
— Irland, a member of the Limestone County Master Gardeners, can be reached at firstname.lastname@example.org. Visit https://mg.aces.edu/limestone for more information on the Limestone County Master Gardeners.