Annual Trampweed

Joey Williamson, Ph.D.
Home & Garden Information Center

Has your lawn suddenly been invaded by a weed that’s going to seed with white, fluffy, dandelion-like seeds? This invasive winter annual weed is Facelis retusa, or Annual Trampweed. It’s been in the state for decades, but with increased annual temperatures and decreased rainfall, this highly competitive weed is colonizing any bare spaces in lawns and along roadsides.

Image depicts Annual Trampweed with its fluffy seed heads.

To control annual trampweed in lawns, homeowners must provide the best conditions for turfgrass growth, and use selective herbicides to eliminate this broadleaf weed. Proper turfgrass care includes taking a soil sample, applying the correct amount of dolomitic limestone to adjust the soil pH or acidity for best grass growth, and fertilizing the grass at the correct times with the appropriate lawn fertilizer. With the reduced rainfall recently, turfgrass needs supplemental watering at the rate of 1" per week. Proper mowing heights for each turfgrass species is also important to maintain a thick grass stand.

In warm season grass lawns, a broad-leaf weed killer (herbicide) should be applied in October/November and again in February/early March. However, do not apply broadleaf weed killers to warm season lawns during their spring green-up. These applications will kill any seedlings that germinated in the fall and those that germinated in the early spring. A 3-way post-emergent herbicide that contains 2,4-D, dicamba, and MCPP will be the best type to control the trampweed. Follow the directions as to rate, but remember to cut the rate in half for use on Centipede and St. Augustine to not injure the grass. Examples of herbicide products with these ingredients are Ortho Weed-B-Gon for Southern Lawns, Bayer Advanced Lawn Southern Weed Killer, and Green Light Wipe-out Broadleaf Weed Killer. These are liquid concentrates that are mixed with water and sprayed over the lawn.

In Fescue lawns that are over seeded annually in October to maintain a thick grass cover, the application of a broad-leaf weed killer should be delayed until February and then applied again in March. This will kill the trampweed plants from seed that germinated during the fall and spring. The fall application is not made because this type of herbicide can injure tender, young fescue seedlings.

Just remember that your trees and shrubs are broad-leafed plants, and this herbicide can injure or kill them, too, if sprayed. Most deciduous trees and shrubs have lost their leaves by November and have not leafed-out again by early March, so applications at these times are less likely to affect them. But do not spray heavily around the root zones of these ornamentals as the herbicide can be taken up by plant roots also. Fortunately, this weed seems to be worse in most cases out in the lawns and farther from trees and shrubs.

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This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.