What Kills Dollarweed but Not Grass?

Dollarweed, also called pennywort, is a broadleaf weed that thrives in warm, wet conditions. With its round, shiny leaves that resemble tiny lily pads, dollarweed may look harmless at first—but left unchecked, it will quickly overtake your lawn. The biggest challenge? Finding a way to kill dollarweed without harming your grass.

The good news is that with the right treatments and lawn care practices, you can keep your turf healthy and weed-free.

Why Dollarweed Shows Up in Lawns

Dollarweed is an opportunistic plant. It usually becomes a problem when:

• Soil stays too damp. Overwatering or poor drainage creates the perfect environment.
• Grass is thin or weak. Bare patches give dollarweed space to spread.
• Nutrient imbalance exists. Underfed lawns are less competitive against weeds.

Identifying and fixing these conditions is just as important as weed control itself.

Selective Herbicides: Targeting Dollarweed, Not Grass

The safest and most effective way to remove dollarweed while protecting turfgrass is to use selective herbicides. These products are designed to target broadleaf weeds without damaging most grass types.

Here are some of the most common active ingredients to look for:

• Atrazine – Works well on dollarweed in St. Augustine and centipede grass.
• 2,4-D, Dicamba, or MCPP – Safe for many warm-season grasses like Bermuda and Zoysia when applied according to label instructions.
• Triclopyr – Another effective option for broadleaf weed control.

⚠️ Always read the product label to ensure it’s safe for your specific grass type, and apply during mild weather when weeds are actively growing.

Natural and Cultural Control Methods

If you prefer a less chemical-heavy approach, or if you want to supplement herbicide use, cultural practices can make a big difference.

• Adjust Watering Habits – Since dollarweed loves wet soil, reduce irrigation. Aim for deep, infrequent watering (about 1 inch per week).
• Improve Drainage – Aerating your lawn and topdressing with sand or compost can help dry out overly soggy areas.
• Mow Properly – Cutting your grass at the correct height for its species strengthens the lawn and shades out weeds.
• Fertilize Strategically – A strong, thick lawn is the best defense. Learn how to do it correctly in this guide on how to apply fertilizer on lawn.

Some homeowners also try natural methods like applying baking soda directly to dollarweed patches, though results vary and it may stress surrounding turf.

Grass Types and Herbicide Compatibility

Not all lawns respond the same way to treatments. It’s important to match your approach to your turf:

• St. Augustine & Centipede Grass – Respond well to atrazine-based herbicides.
• Bermuda & Zoysia Grass – Tolerate 2,4-D and dicamba products.
• Fescue & Cool-Season Grasses – May be more sensitive; always double-check the label.

This step ensures you target the weed without accidentally thinning out your grass.

When to Apply Treatments

Timing matters just as much as product choice. For best results:

• Apply herbicides when dollarweed is young and actively growing.
• Treat in the spring or early summer, before the weed matures and spreads.
• Avoid applying during drought stress or extreme heat, which can damage grass.

Professional Help for Persistent Dollarweed

Even with careful treatment, dollarweed can be tough to eliminate completely—especially if overwatering or soil drainage issues remain. That’s where professional lawn care can save you time and effort.

A local lawn care company can:

• Identify the exact type of weed.
• Choose the safest, most effective treatments for your grass type.
• Apply fertilizers and herbicides at the right time for lasting results.

Dollarweed doesn’t have to take over your turf. With the right mix of selective herbicides, smart watering practices, and consistent lawn care, you can stop it in its tracks and enjoy a healthy, vibrant lawn.

👉 Ready to see results? Let the experts at Ryno Lawn Care help. Explore our lawn fertilization services and discover how we can keep your grass green, thick, and dollarweed-free all season long.