Dollarweed (Hydrocotyle spp.), also called pennywort, is one of the most persistent and frustrating weeds that invade lawns, garden beds, and landscape areas across the southeastern United States. Its round, coin-shaped leaves spread aggressively through underground rhizomes and above-ground stolons, quickly taking over moist areas of your yard.
In this guide, you’ll learn how to positively identify dollarweed, understand why it thrives in your lawn, and discover the most effective natural and chemical control methods to eliminate it permanently.
How to Identify Dollarweed
Dollarweed is easy to identify once you know what to look for. Here are its distinguishing characteristics:
- Leaves: Round, bright green, coin-shaped leaves measuring 1–2 inches in diameter. The stem attaches to the center of the leaf (peltate attachment), like an umbrella, which is the key identifying feature.
- Stems: Slender, upright stems that emerge from underground runners. Each stem supports a single leaf.
- Flowers: Tiny white to greenish-white flowers that appear in small clusters on short stalks from spring through fall.
- Root system: Extensive network of underground rhizomes (horizontal roots) and above-ground stolons (runners) that allow rapid spreading.
- Growth habit: Low-growing, typically 2–6 inches tall. Forms dense mats that smother grass.
Key Identification Feature
The most reliable way to distinguish dollarweed from lookalike plants is the stem attachment. Dollarweed’s stem connects to the center of the leaf underside. Similar-looking plants like dichondra and clover have stems that attach to the leaf edge.
Why Dollarweed Grows in Your Lawn
Dollarweed is an indicator plant — its presence tells you something about your lawn’s growing conditions. Understanding why it’s there is the first step to eliminating it:
| Condition | Why It Favors Dollarweed | Solution |
|---|---|---|
| Excess moisture | Dollarweed is semi-aquatic and thrives in wet soil | Improve drainage, reduce irrigation |
| Overwatering | Frequent shallow watering keeps the soil surface moist | Water deeply but less frequently |
| Poor drainage | Compacted soil or low spots trap water | Aerate soil, regrade low areas |
| Thin or weak turf | Sparse grass allows dollarweed to establish | Overseed, fertilize, and maintain thick turf |
| Shaded areas | Grass struggles in shade, giving dollarweed an advantage | Prune trees, plant shade-tolerant grass varieties |
| Nutrient imbalance | Over-fertilizing with nitrogen in wet conditions | Soil test and balanced fertilization |
Bottom line: Dollarweed is almost always a moisture problem. If you fix the moisture, you fix the dollarweed.
Natural Removal Methods
1. Reduce Watering
This is the single most effective natural control. Switch from frequent, shallow watering to deep, infrequent irrigation. Water your lawn once or twice per week with 1/2–3/4 inch of water per session, allowing the soil surface to dry between waterings. Dollarweed cannot compete in drier conditions.
2. Hand Pulling
Effective for small infestations if you remove the entire root system. Pull after rain when the soil is soft, grasping the plant at its base and extracting the underground runners. Any root fragments left behind will regrow, so be thorough. Dispose of pulled plants in sealed bags, not compost piles.
3. Vinegar Treatment
Horticultural vinegar (20% acetic acid — not household vinegar at 5%) can burn dollarweed foliage on contact. Apply on a sunny day to maximize effectiveness. Note that vinegar is a non-selective contact herbicide and will damage any plant it touches, including your grass. It also doesn’t kill the roots, so repeated applications are necessary.
4. Boiling Water
Pouring boiling water directly onto dollarweed patches kills the foliage and can penetrate shallow roots. This is effective for dollarweed growing in cracks, pavers, or garden bed edges where you don’t need to protect surrounding grass. Multiple applications may be needed.
5. Improve Soil Drainage
Core aerate your lawn annually to reduce compaction and improve water penetration. Fill low spots with topsoil to eliminate areas where water pools. Install French drains or catch basins in chronically wet areas. Once the excess moisture is resolved, dollarweed naturally declines.
6. Strengthen Your Turf
A thick, healthy lawn is the best long-term defense against dollarweed. Overseed thin areas, maintain proper mowing height for your grass type, and follow a balanced fertilization schedule. Thick turf blocks sunlight from reaching dollarweed seeds and makes it harder for stolons to establish.
Chemical Control Options
When natural methods aren’t enough, selective herbicides can target dollarweed without harming your lawn grass. Always read and follow label directions carefully.
Post-Emergent Herbicides
| Active Ingredient | Effectiveness | Grass Safety | Notes |
|---|---|---|---|
| Atrazine | Excellent | Safe for St. Augustine, centipede, zoysiagrass | Apply when temps are below 85°F; restricted in some states |
| Metsulfuron-methyl | Excellent | Safe for most warm-season grasses | Very low application rates; effective and economical |
| 2,4-D + dicamba + mecoprop | Good | Safe for most lawn grasses | Found in many broadleaf weed killers; may need repeat application |
| Penoxsulam | Very good | Safe for St. Augustine and bermudagrass | Newer chemistry; effective on dollarweed |
| Imazaquin | Good | Safe for most warm-season grasses | Best results with surfactant added |
Application Tips
- Apply herbicides when dollarweed is actively growing (spring through early fall).
- Spray on a calm, dry day when rain isn’t expected for 24 hours.
- Add a non-ionic surfactant to improve herbicide adhesion to dollarweed’s waxy leaves.
- Do not mow for 2–3 days before or after application.
- Expect visible results within 1–3 weeks. A second application may be necessary 4–6 weeks later.
Recommended Treatment Schedule
| Season | Action | Details |
|---|---|---|
| Early Spring | Apply pre-emergent herbicide | Prevents new dollarweed from seed germination |
| Late Spring | First post-emergent application | Target actively growing dollarweed |
| Summer | Reduce irrigation frequency | Allow soil surface to dry between waterings |
| Early Fall | Second post-emergent application (if needed) | Catch any regrowth before dormancy |
| Fall | Core aerate & overseed | Strengthen turf to prevent future invasion |
| Year-round | Monitor & hand-pull small patches | Prevent re-establishment from runners |
Prevention Strategies
Once you’ve eliminated dollarweed, keep it from coming back with these ongoing practices:
- Water wisely: Deep, infrequent irrigation (2–3 times per week maximum) discourages dollarweed while strengthening grass roots.
- Maintain thick turf: Mow at the proper height for your grass type and keep the lawn well-fertilized to crowd out weeds.
- Improve drainage: Address any grading issues, install drainage solutions, and aerate compacted soil annually.
- Monitor edges: Dollarweed often invades from adjacent moist areas like drainage ditches, pond edges, or poorly drained neighbors’ yards. Create a barrier with regular herbicide applications along vulnerable borders.
- Soil test annually: Balanced soil pH and nutrients support healthy grass that naturally resists weed invasion.
Proper lawn and landscape maintenance extends to your home’s exterior flooring as well. If dollarweed is growing near your patio or outdoor tile areas, addressing drainage will protect both your lawn and your outdoor living surfaces.
Dollarweed vs. Dichondra: How to Tell Them Apart
| Feature | Dollarweed | Dichondra |
|---|---|---|
| Leaf shape | Round, coin-shaped | Kidney or fan-shaped |
| Stem attachment | Center of leaf (peltate) | Edge of leaf (peltate-absent) |
| Leaf size | 1–2 inches diameter | 0.5–1.5 inches wide |
| Texture | Smooth, slightly waxy | Soft, slightly fuzzy |
| Moisture preference | Very wet conditions | Moderate moisture |
| Growth pattern | Spreads by rhizomes & stolons | Spreads by stolons only |
| Desirability | Always a weed | Sometimes used as ground cover |
Frequently Asked Questions
Will mowing kill dollarweed?
No. Dollarweed grows low to the ground and its leaves sit at or below typical mowing heights. Mowing removes the top growth but doesn’t affect the underground rhizome network that allows it to regrow. In fact, mowing can spread dollarweed fragments to new areas of your lawn.
Does dollarweed die in winter?
In areas with freezing temperatures, dollarweed foliage dies back in winter. However, the underground rhizomes survive and the weed returns vigorously in spring. In frost-free regions like south Florida, dollarweed stays green year-round.
Is dollarweed harmful to pets?
Dollarweed itself is not toxic to dogs, cats, or other pets. In fact, it’s edible for humans too (it’s used in Asian cuisine as “pennywort”). However, herbicides applied to dollarweed can be harmful to pets, so follow all label instructions regarding pet-safe reentry intervals after treatment.
Why does dollarweed keep coming back?
Dollarweed’s persistence comes from its extensive underground rhizome system. Even when you kill all visible leaves, surviving root fragments as small as one inch can regenerate an entire plant. That’s why addressing the underlying moisture problem is essential — chemical treatment alone rarely provides permanent control.
Can I use regular vinegar to kill dollarweed?
Household vinegar (5% acetic acid) can burn dollarweed leaves but generally isn’t strong enough to kill the plant. Horticultural vinegar (20% acetic acid) is more effective but still only kills the foliage, not the roots. Chemical herbicides or moisture management are more reliable long-term solutions.
Does baking soda kill dollarweed?
There’s no scientific evidence that baking soda effectively controls dollarweed. While baking soda can damage some plant foliage, it’s not a reliable weed killer and can alter soil pH in ways that harm your lawn grass. Stick to proven methods like moisture reduction, hand pulling, or selective herbicides.
Last updated: March 2026
