Nimblewill, scientifically known as Muhlenbergia schreberi, is a warm-season grass that has been gaining attention for its versatile characteristics and adaptability. This native warm-season perennial can be a friend or foe, depending on your perspective. Nimblewill is a dense, fine-textured grass that thrives in hot weather. It forms a thick mat with short, narrow leaves and a reclining growth habit. It readily roots at its nodes, spreading quickly and potentially encroaching on your desired turfgrass if it is not controlled properly.
While nimblewill can be a desirable lawn grass for homeowners in the South, it has a widespread reputation of being a tenacious weed for those further north. Its creeping habit and ability to root from its nodes make it a persistent invader of cool-season lawns. Pulling it out can be a frustrating exercise in futility, as every fragment seems to sprout into a new plant.
Identifying Nimblewill
Photo By Larry Allain, U.S. Geological Survey
Nimblewill thrives in moist, shady areas and boasts two distinct appearances depending on the season:
Summertime: Under the warm summer sun, nimblewill thrives and grows rapidly. It forms a dense, low-maintenance lawn with fine-textured, blue-green foliage. Their striking appearance stands out among other grasses and fortunately makes it obvious to spot and treat.
Wintertime: However, as temperatures drop, nimblewill sheds its summer charm. It turns brown and dormant, leaving behind unsightly straw-like patches that can be mistaken for dead grass. This dormant phase can be frustrating for homeowners who crave year-round green.
Seasonal appearances aren’t the only way to identify nimblewill. Here are some other key characteristics:
Fine Texture: Nimblewill blades are thin and narrow, resembling bermudagrass but with a softer feel.
Pale Green Color: Compared to the deep green of many lawn grasses, nimblewill has a lighter, bluish-green hue.
Creeping Habit: Nimblewill spreads aggressively through stolons (aboveground runners) and rhizomes (underground stems), forming dense mats.
Leaf Arrangement: Nimblewill leaves alternate along the stem, unlike the opposite arrangement of many grasses.
Seed Heads: In late summer/early fall, nimblewill produces small, purplish seed heads that resemble millet.
Managing & Controlling Nimblewill
Photo By Larry Allain, U.S. Geological Survey
Nimblewill is a warm-season grass that can be a persistent weed in lawns, especially in the southern United States. It spreads quickly by stolons (runners) and rhizomes (underground stems), making it difficult to control. Here are some methods you can use to manage and control nimblewill:
Cultural Control
Mow High: Maintain a mowing height of 3 inches or more. This will help shade out the nimblewill and give your desired grass a competitive advantage.
Fertilize Properly: Apply a balanced fertilizer according to your soil test results. This will help your desired grass grow strong and healthy, making it more resistant to nimblewill invasion.
Irrigate Deeply & Infrequently: Water your lawn deeply and infrequently to encourage deep root growth. This will make your desired grass more drought-tolerant than nimblewill.
Overseed: In the fall, overseed your lawn with a cool-season grass, such as Kentucky bluegrass or tall fescue. This will help crowd out the nimblewill.
Mechanical Control
Hand-Pulling: This is only effective for small infestations. Be sure to remove all of the roots, or the nimblewill will grow back.
Digging: You can also dig up small patches of nimblewill. Be sure to get all of the roots, or the nimblewill will grow back.
Chemical Control
Non-Selective Herbicides: Glyphosate (Roundup) is a non-selective herbicide that will kill all vegetation, including nimblewill. Be careful not to apply it to your desired grass.
Selective Herbicides: There are a few selective herbicides that will kill nimblewill but not most other lawn grasses. These herbicides include mesotrione (Tenacity) and topramezone (Pylex).
Keep in mind that patience and persistence are the keys to getting rid of nimblewill. Don't expect to see results overnight, and remember that you may need to use a combination of methods to control nimblewill effectively. Remember to monitor your lawn for new infestations. Nimblewill can be sneaky, so it's important to watch for it. If the process ever proves to be too overwhelming, contact a lawn care professional, like those at Brothers Lawn Service, and let them guide you to rid your lawn of this pesky weed.
