How To Control Dollarweed (Pennywort) in Your Lawn
By: Julie Day
Dollarweed thriving near a seaside outdoor faucet.
If you live in a warm or coastal climate, you’ve likely experienced the invasion of dollarweed (also called pennywort) in your lawn or garden. Dollarweed is caused by excess moisture, and it thrives in areas of poor drainage, excess irrigation, poor soil, and thin turf. Here’s what you need to know to control dollar weed in your yard.
Dollarweed has small, round, shiny leaves that are shaped like coins. It’s often mistaken for dichondra, a weed with similar round leaves, but the difference is in the stem. Dollarweed’s stem comes directly out of the center of the leaf, while dichondra’s stem is attached at the edge of the leaf. As weeds go, dollarweed’s glossy leaves are actually rather pretty, and if you can keep it under control, dollarweed can serve as a groundcover in impossible areas.
The main culprit in a dollarweed invasion of your lawn is too much water. Whether it’s caused by over-irrigating, too much rain, or poor soil drainage, thin turf in wet areas can quickly be taken over by this tough and hardy plant. Dollarweed spreads both by seeds and underground roots, making it very difficult to eliminate. Like many weeds, you may find that you’re managing dollarweed rather than eradicating it.
How To Control Dollarweed
If you have dollarweed in your yard, here are some tips on how to reclaim your turf:
- Improve Grass: The presence of weeds is a sign that your grass isn’t healthy, and thick turf is by far your best defense. Take steps to identify why your grass is weak, and focus on getting your lawn healthy. Treat any diseases, insect infestations, soil problems, and maintain proper mowing height.
- Reduce Irrigation: Use a rain gauge to make sure your lawn is receiving one inch of water per week. If it’s getting a lot more than that, reduce irrigation to keep your lawn from becoming soggy which can discourage your grass and encourage dollarweed.
- Improve Drainage: Take steps to improve the drainage in your lawn to reduce the moist conditions that attract dollarweed. It may be as simple as aerating and top-dressing your lawn to improve the soil. Or it may require a more costly solution, such as an underground drainage system.
- Remove Weeds: Hand pull dollarweed whenever you can, and be sure to get all the roots.
- Herbicides: If all else fails, you may need to apply a broadleaf herbicide to help control dollarweed. Apply products while the weeds are actively growing. Choose an herbicide rated both for dollarweed and your grass type. Dollarweed is a common invader of warm-season lawns, which can be sensitive to generic herbicides. Some success with dollarweed has been reported with Atrizine (which requires professional application), Image (Imazaquin) and 2,4-D, although all of these products pose health hazards. You can also paint a full-spectrum herbicide (such as Roundup) directly on the leaves of dollarweed.
- Organic Solutions: Natural, organic products, such as vinegar, may also work on dollarweed if repeatedly applied.