Virginia Buttonweed

Virginia buttonweed (Diodia virginiana) is a mat-forming perennial that thrives in poorly drained areas or under excessively moist soil conditions in lawns. Leaves are lance-shaped and dark green.
Close-up of Bugwood photo 1604118. John Ruter, University of Georgia, Bugwood.org

Virginia buttonweed (Diodia virginiana) is a challenging to control turfgrass weed that has recently become a prevalent weed in South Carolina lawns. This perennial weed is deeply rooted, produces belowground and aboveground flowers, and spreads by rhizomes (underground stems), as well as by stem pieces cut and distributed during mowing or string trimming. Virginia buttonweed becomes more troublesome and thrives in poorly drained or overly moist lawns caused by excessive rainfall or frequent irrigation.

Its shiny, dark green, lance-shaped leaves are oppositely arranged on the stems and have no petioles (stalks that attach leaves to stems). By late summer, leaves may turn yellow-green due to a viral infection. The flowers are tubular and white with four petals, which are arranged in a four-pointed star. If left uncontrolled, this mat-forming weed can smother out turfgrass.

The flowers of Virginia buttonweed (Diodia virginiana) are tubular, white, and have four petals.
Close-up of Bugwood photo 5428015. Rebekah D. Wallace, University of Georgia, Bugwood.org

During the late summer, many of the Virginia buttonweed (Diodia virginiana) leaves will become yellow-green and mottled because of an infection by an unknown virus.
Joey Williamson, ©2020 HGIC, Clemson Extension

Cultural Controls: Limit Virginia buttonweed growth by maintaining a healthy and dense turfgrass. Water the lawn deeply but infrequently to allow the surface soils to dry between watering, thus improving turfgrass root depth. For more information on irrigation, please see HGIC 1207, Watering Lawns. Additionally, correct any drainage problems to reduce wet areas within the lawn.

Core aerate the lawn to improve internal soil drainage, reduce soil compaction, and aid in root growth. For more information on core aeration, please see HGIC 1200, Aerating Lawns.

Apply fertilizers and lime based on soil test results. Fertilizer and lime recommendations are turfgrass specific. Please see HGIC 1652, Soil Testing, for sampling procedures.

Mow the lawn at the correct height for the turfgrass species. Mowing excessively low both stresses the turfgrass and causes the mower to cut and spread pieces of the weed’s stems. Virginia buttonweed tolerates mowing as low as ½ inch, and stem pieces can easily root under moist conditions. A lawn mowed at the correct height encourages dense turfgrass growth and helps shade out the Virginia buttonweed. For correct mowing heights, please see HGIC 1205, Mowing Lawns.

If the lawn thatch layer is greater than ½ inch, consider dethatching the lawn at the appropriate time. For more information about dethatching, please see HGIC 2360, Controlling Thatch in Lawns.

Hand pulling Virginia buttonweed is ineffective as a control because pieces of roots and stems that remain can re-sprout.

Chemical Controls: Managing Virginia buttonweed in a lawn may require two years of post-emergence herbicide applications. For best control, begin herbicide applications in the spring when the plants are coming out of dormancy and producing tender, new growth. Spring herbicide applications also help control the young seedlings growing in the lawn and prevent large mats of growth that can smother out turfgrass by late summer. In late summer, older Virginia buttonweed plants are much more tolerant of selective herbicides, making controls less effective.

Apply metsulfuron (Quali-Pro MSM) or Celsius WG sprays in the spring when the Virginia buttonweed begins to green-up. Apply a follow-up application four to six weeks later. These products are safe to apply when the temperature is greater than 85 °F. In contrast, products containing 2,4-D may injure centipedegrass or St. Augustinegrass above 85 °F. Metsulfuron (as the only ingredient in a product like MSM) or Celsius WG can be sprayed on weeds in warm-season turfgrass during the lawn’s spring green-up period. Celsius WG provides good to excellent control of Virginia buttonweed, while metsulfuron offers good control.

Blindside Herbicide WDG contains metsulfuron and sulfentrazone and may give better control of Virgina buttonweed than metsulfuron alone. Make a second application 21 days after the initial application.

Fahrenheit Herbicide contains metsulfuron and dicamba. Make a repeat application in 4 to 6 weeks for control. Do not make Fahrenheit application if temperatures will exceed 85 degrees.

Do not apply metsulfuron products or Celsius WG to a tall fescue lawn. Do not apply metsulfuron products beneath the dripline of trees and shrubs. Read all label precautions and restrictions.

Use 3-way lawn herbicides containing 2,4-D, dicamba, mecoprop, and carfentrazone on bermudagrass, centipedegrass, zoysiagrass, St.Augustinegrass, and tall fescue. However, only apply these products after warm-season turfgrasses have completely greened-up in late spring. The 2,4-D, dicamba, mecoprop, and carfentrazone combination herbicides will suppress new Virginia buttonweed growth in the spring and kill the seedlings. Do not make spray applications if the daily temperature is greater than 90 degrees. A second application can be made with most products after 30 days.

Treat large areas of Virginia buttonweed with little to no turfgrass with a 3% glyphosate spray. Read the label directions of forty-one percent glyphosate products for instructions on mixing in a pump-up sprayer. Re-sod a couple of weeks after the last glyphosate application once the Virginia buttonweed is eliminated.

See Table 1 below for brands and products, including more notes on the use of metsulfuron, Celsius WG, glyphosate, and combination broadleaf weed herbicides.

Table 1. Examples of Post-emergence Herbicides for Virginia Buttonweed Management in Residential Turfgrass.

Pesticides are updated annually. Last updates were done on /21 by Joey Williamson.

Originally published 02/20