How to Control Dollar Weed & Oxalis Organically

Dollar weed and oxalis are two of the most stubborn weeds in Florida landscapes, often confused for each other. If you’ve struggled to get rid of them, you’re not alone. Both thrive in overwatered areas, spread aggressively, and are resistant to many traditional weed killers—including Roundup.

Why Are Dollar Weed & Oxalis So Hard to Control?

Dollar weed (Hydrocotyle spp.) loves moist, compacted soil, making it a common problem in lawns and garden beds with excess irrigation. It spreads through rhizomes and underground runners, which makes it difficult to eliminate completely.

Oxalis (Oxalis spp.), often mistaken for clover, spreads through underground bulbs and seeds. Even if you pull it up, tiny bulbs left behind will sprout new growth, making it just as relentless as dollar weed.

Many people attempt to spray Roundup, only to see the weeds return in a few weeks. That’s because chemical sprays kill the top growth but don’t eliminate the underground root systems.

The Best Organic Method: Smothering with Cardboard & Mulch

If reducing irrigation isn’t an option, one of the best organic strategies is smothering these weeds with a thick layer of cardboard and mulch.

Step-by-Step Smothering Method:

1. Lay down thick cardboard (two to three layers) over the affected area.
2. Overlap the edges so weeds can’t poke through gaps.
3. Cover with 3-4 inches of mulch (hardwood mulch works best for long-term suppression).
4. Check every few months—while this method greatly reduces maintenance, both dollar weed and oxalis are persistent and will eventually try to return.

This approach cuts down on maintenance, but in high-irrigation areas, you’ll need monthly touch-ups to keep them from coming back.

Using Ground Covers for Long-Term Control

To make your garden beds more resistant to dollar weed and oxalis, planting aggressive ground covers can help smother them naturally.

One great option is mint—it has strong roots that outcompete weeds in shady areas. However, mint spreads aggressively, so it’s best used in contained areas where it won’t take over your other plants. In sunnier areas we like to use sunshine mimosa but this area being shady we chose mint.

Unfortunately, in this bed, the lawn care worker mistook the mint for a weed and cut it down before it could establish. If you use this method, be sure to inform your lawn care team to leave the mint untouched so it can do its job.

Final Thoughts

Dollar weed and oxalis are tough, but organic control is possible with the right strategy. If you’re dealing with persistent weeds, a combination of smothering, proper irrigation, and competitive planting will help keep them under control.

Need help tackling tough weeds in your garden? Weed Wise Gardens offers organic, chemical-free weed control solutions that work with nature—not against it.