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.
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 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 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 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. Do not apply metsulfuron or Celsius WG to a tall fescue lawn.
Use home lawn-care 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.
Treat large areas of Virginia buttonweed with little to no turfgrass with a 3% glyphosate spray. Forty-one percent glyphosate products with instructions for diluting in a pump-up sprayer are available. 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.
|Brands & Specific Products||Herbicide Active Ingredient||% Active Ingredient
|Site Labeled for Use|
|Ferti-lome Weed Free Zone Concentrate; & RTS1||2,4-D
& St. Augustinegrass
An application may be repeated once after 30 days.
|Ferti-lome Weed Free Zone RTU2||MCPA
|Bonide Weed Beater Ultra Concentrate||MCPA
|Celsius WG Herbicide3||Thiencarbazone
& St. Augustinegrass4
& St. Augustinegrass
|Martin’s Top Shot Weed Killer for Lawns (Discontinued, but may still be available)||Metsulfuron||25.0||Bermudagrass
& St. Augustinegrass
|Ace Concentrate Weed &
Grass KillerBonide Kleenup Grass & Weed Killer Concentrate; & RTU2
Eliminator Weed & Grass
Hi-Yield Super Concentrate Killzall Weed & Grass Killer
Knockout Weed & Grass Killer Super Concentrate
Martin’s Eraser Systemic Weed & Grass Killer
Monterey Remuda Full Strength 41% Glyphosate
Quick Kill Grass & Weed Killer
Roundup Original Concentrate
Roundup Pro Herbicide
Southern States Grass &
Tiger Brand Quick Kill Concentrate
Total Kill Pro Weed & Grass Killer Herbicide
Ultra Kill Weed & Grass Killer Concentrate
Zep Enforcer Weed Defeat III
|Glyphosate||41% (most brands)||For use within the lawn as spot spraying to kill large patches of Virginia buttonweed. Then re-sod or re-seed these areas after doveweed is dead (a couple of weeks).|
|1 RTS: Ready-to-Spray (hose-end sprayer)
2 RTU: Ready-to-Use (pre-mixed spray bottle)
3 This mix of active ingredients requires the addition of 0.25% by volume (2 teaspoons per gallon of water) of a non-ionic surfactant (such as Hi-Yield Spreader Sticker, Southern Ag Surfactant for Herbicides, or Bonide Turbo Spreader Sticker). This is a wetter-sticker agent to aid in weed control. Repeat Celsius WG application in 4 to 6 weeks for the best control.
4 Spot treatments of Celsius WG to St. Augustinegrass at temperatures above 90 degrees may cause temporary growth regulation. Celsius WP is not for use on fescue lawns.
5 Do not apply metsulfuron to turfgrass that is less than one year old. Do not apply beneath the dripline of trees and shrubs.
Note: Do not apply any post-emergence herbicides, except Celsius WG Herbicide, to lawns during the spring green-up of turfgrass. For other products, wait until the turfgrass is fully green in late spring. Follow all product label directions for mixing and safe use.