Prepared by Morgan E. Judy, Extension Agent, Orangeburg County, Clemson University. (New 06/09. Pesticides updated 09/10.)
Nothing designates spring’s arrival like walking barefoot on a lawn of lush, green grass. This pleasant experience can often turn into a painful, sticky situation with the presence of lawn burweed. Other names for this weed are spurweed and stickerweed. Lawn burweed (Soliva sessilis) is a winter annual that germinates throughout thin turf in the fall months as temperatures cool. It remains small and inconspicuous during the cold winter months. However, as temperatures warm in the early spring, lawn burweed initiates a period of rapid growth and begins to form spine-tipped burs in the leaf axils. The seed is contained within the hooked bur.
Lawn burweed is a low-growing, freely branched winter annual. It has opposite, sparsely hairy leaves that are twice divided into narrow segments or lobes.
Lawn burweed growth habit
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Leaves are approximately ½ to 1½ inches long and ¼ to ½ inch wide. It has small (¼ inch or less in width), inconspicuous flowers in the spring. It attains an overall diameter of 6 inches and a height of 3-4 inches. The most prominent identifying characteristic of lawn burweed is its spine-tipped burs which are often hard to see but easily felt.
Lawn burweed leaves and fruiting head
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Maintain a healthy, dense lawn by fertilizing and liming according to soil test results and mowing at the proper height and frequency for your specific turfgrass. Healthy lawn grasses can outcompete burweed for light, water and nutrients and reduce the level of infestation. For more information on growing healthy turfgrass, see HGIC 1201, Fertilizing Lawns; HGIC 1205, Mowing Lawns; and HGIC 1207, Watering Lawns.
Postemergence Control: The key factor to effectively controlling lawn burweed is to apply a postemergence herbicide during the winter months of December, January and February. The weed is smaller and easier to control during this time of year and has not yet developed the spine-tipped burs. Control is not impossible in March, April, and May, but the spines have already formed by this time and will remain after the weed dies. Because lawn burweed is a winter annual, it will begin to die in late spring as air temperatures reach 90 °F. Once the weed has reached a more mature state, multiple herbicide applications may be necessary which increases the potential for turfgrass injury. Dead or alive, lawn burweed poses a painful problem. The only solution to this is early identification and control.
A three-way herbicide may be used on bermudagrass, zoysiagrass, centipedegrass, St. Augustinegrass and tall fescue. The active ingredients of a three-way herbicide often include the following broadleaf weed killers: 2,4-D, dicamba, and mecoprop (MCPP). Examples of a three-way herbicide are Ferti-lome Weed-Out Lawn Weed Killer with Trimec®, Bayer Advanced Southern Weed Killer for Lawns, Spectracide Weed Stop Weed Killer for Lawns, Southern Ag Lawn Weed Killer with Trimec®, and Lilly Miller Lawn Weed Killer Concentrate.
Note: Herbicides containing 2,4-D should be applied at a reduced rate on St. Augustinegrass and centipedegrass to prevent damage to these lawns. If a second application is needed, apply the herbicide in spot treatments. Repeated applications of a three-way herbicide should be spaced according to label directions.
In addition to three-way herbicides, there are several other herbicides that can be used for lawn burweed control in home lawns. Atrazine may be used for control in centipedegrass and St. Augustinegrass. Atrazine applied in November will have postemergence activity against newly sprouted lawn burweed seedlings and also will have preemergence activity against those that have not yet germinated during the fall. Examples of products containing atrazine for home lawns are Southern Ag Atrazine Weed Killer, Hi-Yield Atrazine Weed Killer, Image for St. Augustinegrass & Centipedegrass with Atrazine and Spectracide Weed Stop for Lawns Concentrate for St. Augustine & Centipede Lawns.
Metsulfuron (such as in Manor and Blade) can be used for lawn burweed control in bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass. Metsulfuron is packaged for landscape professionals. Due to the cost and application rate of this selective herbicide, it may be more practical to hire a landscape professional to apply the treatment. A non-ionic surfactant (such as Southern Ag Surfactant for Herbicides) is required at 2 teaspoons per gallon of spray mix for best control. Do not apply metsulfuron to lawn if over-seeded with annual ryegrass or over-seed for 8 weeks after application. Do not plant woody ornamentals in treated areas for one year after application of metsulfuron. Do not apply metsulfuron herbicides within two times the width of the drip line of desirable hardwood trees.
CAUTION: Postemergence herbicides should not be applied during spring transition (green-up of lawn) or when air temperatures exceed 90 ºF as this can cause severe damage to the turfgrass. A newly seeded lawn should be mowed a minimum of three times before applying an herbicide.
|Herbicide||Bermudagrass||Centipedegrass||St. Augustinegrass||Tall Fescue||Zoysiagrass|
|S = Safe at labeled rates
I = Intermediate safety, use at reduced rates
NR = Not registered for use on and/or damages this turfgrass
D = Fully dormant turf only.
|(3- way) 2,4-D +
MCPP + dicamba
Preemergence Control: Isoxaben is a preemergence herbicide for control of lawn burweed, as well as many winter broadleaf weeds in bermudagrass, centipedegrass, St. Augustinegrass, zoysiagrass and tall fescue. Apply isoxaben in late September to early October before the winter weeds germinate. Do not reseed or overseed within 60 days of application, and do not apply to newly seeded lawns until the lawn has been mowed three times. An example of a home lawn granular product containing isoxaben is Green Light Portrait Broadleaf Weed Preventer. Granular preemergence herbicides must be activated by ½ inch of rainfall or irrigation.
Note: Read and follow all label instructions when using herbicides. Repeat applications 10 to 14 days apart may be required for acceptable control. Do not mow within 48 hours after application of most herbicides. Most postemergence herbicides need to dry on the leaf surface before irrigation or rainfall occurs.
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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.