Lawn burweed, also known as spurweed and stickerweed, can be painful when walking across the lawn. Lawn burweed (Soliva sessilis) is a winter annual that germinates during cool temperatures throughout fall. Lawn burweed will remain small during the winter months, but when temperatures increase in early spring, the weed will rapidly grow and form spine-tipped burs.
Lawn burweed’s leaves are 1/2 to 1 1/2 inches long and 1/4 to 1/2 inch wide. In the spring, small flowers (1/4 inch or less) will begin to show. The spine-tipped burs are often hard to see, but easily felt, especially with bare feet.
Maintaining a healthy, dense lawn will help outcompete burweed for light, water, and nutrients and reduce the infestation level.
During the winter months (December, January, and February) are the best time to apply a post-emergence herbicide. The weed is small at this time and has not developed the spine-tipped burs. Control is not impossible in March, April, and May, but the spines will have already developed during this time and will remain after the weed dies. Winter annual weeds begin to die in late spring when air temperatures reach 90F. When lawn burweed reaches a more mature state, multiple herbicides applications will be necessary which increases the chance for turfgrass injury.
Atrazine, a three-way herbicide (2, 4-D + MCPP + dicamba), metsulfuron, or a herbicide mix of thiencarbazone, iodosulfuron and dicamba are recommended post-emergence herbicides that depending on the type of turfgrass you have. Remember to read the label to ensure the herbicide is safe for your grass. Atrazine is safe at label rates for centipede and St. Augustine, can be used on fully dormant Bermuda, but can damage tall fescue or Zoysia. A 3-way herbicide 2, 4-D + MCPP + dicamba) can be used safe at labeled rates on Bermuda, tall fescue, and Zoysia, and at reduced rates on centipede and St. Augustine. Metsulfuron can be used safe at labeled rates on Bermuda, centipede, Zoysia, and St. Augustine, but is not recommended on tall fescue. Thiencarbazone, iodosulfuron and dicamba are safe at labeled rates for Bermuda, centipede, St. Augustine, and Zoysia, but is not recommended on tall fescue. Read and follow all label instructions when using herbicides. Repeat application 10 to 14 days apart may be required for acceptable control. Refrain from mowing within 48 hours after application.
Atrazine applied in November will have post-emergence activity on newly sprouted lawn burweed seedlings and those that have not yet germinated during the fall. Atrazine should not be applied to lawns in areas with high water tables or within two times the width of the drip line of desirable hardwood trees and shrubs.
Most post-emergence herbicides should not be applied during the green-up of the lawn, known as the spring transition, or when air temperatures exceed 90F. A newly seeded lawn should be mowed at least three times before applying herbicides. For more information on lawn burweed or specific product brands, please visit the Home and Garden Information Center website at hgic.clemson.edu.
Tune in on Tuesday nights to watch “Making it Grow” at 7 p.m. on SCETV or mig.org. Email Outen at callenb@clemson.edu.
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