Many consider Virginia buttonweed a nuisance due to its aggressive nature, adaptability, and resilience against herbicides. Learning how to control Virginia buttonweed can save your turf and your other plants. Combine proper lawn care with manual removal and post-emergent herbicides to remove this pesky plant for good.
Virginia buttonweed (Diodia virginiana) is a warm-season perennial weed often found in lawns or gardens in the southeastern United States. It features small, glossy, dark-green leaves that grow in pairs along the stem and clusters of small white or pink flowers resembling stars. Buttonweed spreads via seeds, stem fragments, and rhizomes and forms extremely dense mats in lawns.
This plant thrives in moist or wet conditions, causing problems in poorly drained or overwatered lawns or near ponds, streams, and other water sources. Once established, it can also tolerate drought, making it one of the most challenging weeds around.
To control Virginia buttonweed and minimize damage to your lawn, combine proper lawn care with manual removal and chemical treatments such as post-emergent herbicides.
Proper lawn care
Certain lawn care practices can maintain a healthy lawn and discourage the growth of Virginia buttonweed:
Irrigate your lawn correctly
Don’t overwater the lawn. Since this weed thrives in damp environments, controlling moisture levels is essential to prevent its spread. Water deeply but infrequently, providing about 1 inch of water a week, including rainfall. Consider current temperatures and increase that amount to 1 ½ in a drought or extreme heat.
Divide your watering into two or three sessions a week, and set your sprinkler output to 30 minutes (which is how long it takes to accumulate around half an inch of water). Watering correctly encourages deep grass root growth and reduces surface moisture.
Improve soil structure
Healthy soil fosters healthy grass that can outcompete weeds like Virginia buttonweed. To determine your soil’s composition and possible deficiencies, conduct a soil test. Based on the soil test report, amend the soil with the right materials, such as gypsum for heavy clay soil or organic matter for sandy soil to improve water retention.
Improve soil drainage
Well-draining soil reduces excess moisture and limits the growth and spread of buttonweed. To improve your soil’s drainage:
- Dethatch: When you dethatch, you clear the layer of dead and living organic matter that accumulates between the soil’s surface and your grass blades. Thatch acts like a sponge, absorbing water and preventing it from penetrating the soil. This can cause surface standing water. Remove anything thicker than half an inch.
- Aerate the lawn regularly: Lawn aeration reduces compaction and improves air, water, and nutrient circulation at the roots. You can use a lawn aerator to make small holes in the soil and create the proper channels (also called core aeration). Aerate cool-season grass in the spring and fall and warm-season grass in late spring to early summer.
- Add organic matter: This improves soil texture, enhances water penetration, and increases its ability to retain moisture while letting excess water drain. After aerating, spread a layer of aged manure, compost, or shredded leaves over the lawn. Lightly rake it into the soil, ensuring it fills the holes made by the aerator for the best results.
- Create proper lawn grading: Identify any low spots where water can collect and fill them in with topsoil to create a slope that directs water away from those areas.
- Install a drainage system: This can help manage excess water in areas naturally prone to waterlogging. French drains or trench drains are excellent at redirecting water away from the lawn.
Mow your lawn properly
Mowing your lawn correctly keeps grass healthy, manicured, and unattractive to weeds such as Virginia buttonweed. Some helpful tips and tricks to remember:
- Keep your lawn mower blades sharp. Dull mower blades rip grass rather than cut it cleanly. Once it’s torn, your grass will become weak, stressed, and less able to fight off weeds. It also creates bare patches of soil, allowing Virginia buttonweed to establish itself.
- Match the cutting height to your grass type, even if it looks different from your neighbor’s. This guide can help:
| Grass name | Grass type | Recommended mowing height |
| Bermudagrass | Warm season | 1-2 inches |
| Centipedegrass | Warm season | 1-1.5 inches |
| St. Augustinegrass | Warm season | 2.5-4 inches |
| Zoysiagrass | Warm season | 1-2.5 inches |
| Tall fescue | Cool season | 3.5-4 inches |
- Follow the rule of thirds: Never cut more than one-third of the blade’s length. For example, if the grass is 3 inches tall, don’t cut more than 1 inch. Mowing taller promotes strong roots and helps shade out Virginia buttonweed. Mowing too low (scalping) stresses the lawn and blocks photosynthesis (the process plants use to create energy).
Fertilize your lawn
Fertilize your lawn to promote dense, healthy turfgrass and prevent Virginia buttonweed. Well-maintained turfgrass can compete against weeds, has better resilience, and recovers more quickly from stress.
Look for a balanced fertilizer suited for your grass type, containing a mix of macronutrients, such as nitrogen, phosphorus, and potassium. Choose a fertilizer based on your soil test results and what nutrients your lawn needs. Fertilize cool-season grass in spring or fall, and warm-season grass in late spring to early summer.
Don’t overfertilize in your efforts to prevent buttonweed. This can work against you and damage your lawn.
Manual removal
Hand-pulling can prove effective if you have a small Virginia buttonweed infestation. Extract the weeds when the soil is moist (either from irrigation or rainfall) to get the entire root system. Remove all parts of the plant to prevent regrowth.
For larger Virginia buttonweed patches, use a garden fork to dig out the weed entirely. Refill the holes with soil and overseed with turfgrass to prevent new weeds from sprouting.
Manual pulling may not always yield the wanted results, as Virginia buttonweed can regrow from any stems or root particles left behind.
Post-emergent herbicides
To effectively control Virginia buttonweed, use a selective post-emergent herbicide when the weed first sprouts in the spring and is young. Selective herbicides enter the plant and move throughout its tissues, targeting the entire plant.
Don’t wait until summer, as the weed will grow dense and kill your lawn by then. Also, according to the LSU AgCenter, using 2,4-D when temperatures exceed 85 degrees Fahrenheit can severely damage centipedegrass and St. Augustinegrass. Apply herbicide four or five times during the summer (or as needed), but always spot-treat to avoid turf damage.
Look for products with the following ingredients:
- 2,4-D, mecoprop (MCPP), dicamba, and carfentrazone: This 4-way herbicide cocktail targets broadleaf weeds such as Virginia buttonweed. When used correctly, it disrupts cell division, causes abnormal growth, kills plant foliage, and disrupts photosynthesis (necessary for plant energy).
- Triclopyr: This ingredient kills buttonweed by causing uncontrolled hormonal growth. It works on both cool-season and warm-season grass.
- Glyphosate: Disrupts amino acid synthesis in plants, which is vital for growth. However, due to its non-selective nature, it kills any plant it touches, including turfgrass. The Clemson Cooperative Extension recommends a 3% glyphosate spray in areas with minimal or no turfgrass but heavy buttonweed growth.
Pro tip: Pre-emergent herbicides have not proven very successful in eliminating this stubborn weed, and results have been inconsistent.
Clean lawn care equipment and footwear after working in infested areas and avoid moving soil or plants from those same areas.
Also, remove grass clippings if you’ve mowed over the weed. They can contain seeds that will germinate and spread buttonweed to other parts of your lawn.
Dense, carpet-like grasses such as bermudagrass, Zoysiagrass, and St. Augustinegrass can compete against Virginia buttonweed, provided they’re well-maintained. These grasses grow vigorously, reduce the space available for weeds to grow, and shade the soil, preventing weed establishment.
Buttonweed isn’t known to be toxic, but it can cause skin irritation in some pets and people. To avoid any health problems, prevent your furry friends from ingesting the weed.
To give your lawn the best chance at thriving, managing weeds like Virginia buttonweed is a must.
But not everyone’s cut out for lawn care or even has the time for it. If you would prefer professional assistance, reach out to a local Lawn Love expert. They can care for your lawn and make sure weeds never invade again.
Main Photo Credit: Jomegat | Wikimedia Commons | CC BY-SA 3.0
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