What Kills Dollarweed but Not Grass? | Selective Herbicide Guide

Selective broadleaf herbicides containing atrazine, 2,4-D, or dicamba kill dollarweed without harming grass when matched to the correct turf type.

Dollarweed is the glossy, round-leaf invader that turns wet spots in a lawn into a carpet of green coins. The good news: you can knock it out without torching the surrounding grass. The trick is picking the right active ingredient for your turf species and fixing the wet soil that brings dollarweed back every season. Here is what works for each lawn type and what to check before you spray.

Why Dollarweed Grows in Your Lawn

Dollarweed (Hydrocotyle species) thrives in soggy, poorly drained soil. It spreads by seeds, rhizomes, and tubers, meaning a single missed patch can repopulate a whole section of yard. Before any herbicide application, the most important long-term step is reducing soil moisture. Fewer, deeper waterings, correcting drainage issues, and adding French drains or regrading low spots will make future treatments more effective.

Selective Herbicides That Work on Dollarweed

The right active ingredient depends entirely on your grass type. Dollarweed is a broadleaf weed, so broadleaf-selective herbicides are the safe route. Here are the three main options:

• Atrazine — the standard choice for St. Augustine and centipede grass lawns. It kills dollarweed while leaving these sensitive southern turfgrasses alone. Apply in spring when weeds are young and actively growing.
• 2,4-D and dicamba — effective on Bermuda and zoysia lawns. These are the active ingredients in many common broadleaf weed killers; always check the label to confirm your turf species is listed.
• Imazaquin — works best on small dollarweed plants in early spring. It is selective but only safe around landscape plants the label explicitly lists; do not apply near root zones of unlisted ornamentals.

For a detailed comparison of the best commercial products to use on each grass type, check our roundup of the top dollarweed herbicides complete with application notes.

Application Steps for Best Results

Getting the chemistry right is only half the job. How and when you apply matters just as much:

• Check the label first. Confirm your turfgrass species AND any ornamental plant restrictions are included. Products safe for Bermuda may damage St. Augustine.
• Treat in spring. Dollarweed is most vulnerable when it is small and actively growing. A spring application catches it before flower heads form.
• Apply on a calm, dry day. Avoid windy conditions that cause drift onto flower beds or vegetable gardens. Shield nearby ornamentals with cardboard or a piece of plywood during spot treatment.
• Skip stressed lawns. Herbicides work poorly during drought or extreme heat. Wait until the grass and weeds are both actively growing and not moisture-stressed.

What NOT to Use — Common Mistakes

Three mistakes send homeowners back to square one every season. First, grabbing a non-selective product like glyphosate and spraying the whole patch. Glyphosate kills dollarweed but also kills the grass around it — use it only in bare soil areas or where no desirable plants are nearby. Second, treating the weed without fixing the wet soil; dollarweed returns quickly in persistently wet areas. Third, relying on household remedies. Vinegar, boiling water, baking soda, and sugar water are all non-selective and will damage or kill whatever grass they contact. They also do not reach the root system effectively, so dollarweed rebounds from its underground tubers.

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