Dollarweed

What is dollarweed?

Dollarweed is a native, low-growing perennial pennywort that thrives wherever soil stays wet. It is common in lawns across the South, where it usually signals that the turf is getting more water than it needs. dollarweed identification is about as easy as weed ID gets: look for glossy, round, scalloped leaves roughly the size of a silver dollar, each held up on a long stalk attached to the middle of the leaf like a tiny umbrella or lily pad.

It spreads by creeping rhizomes that link leaves together in chains, by small tubers and by seed, and it can even float and keep growing in water. That lets it move quickly through thin, soggy turf and regrow from pieces left behind after digging, so Clemson Extension considers wiping it out completely unrealistic and focuses on keeping it in check. The good news is that it responds to better watering habits: University of Florida research cited by Clemson found that watering less often reduced dollarweed.

Dollarweed identification: what to look for

Pick a leaf and turn it over. A dollarweed leaf is round with a wavy, scalloped edge, and its stalk joins the blade right in the center underneath. That center attachment is the quickest way to rule out look-alikes such as dichondra, whose stalk joins at the leaf edge. Pull gently on one leaf and you will often find it connected underground to several others by a chain of rhizomes.

• Leaves: Round to slightly kidney-shaped, shiny and a little leathery or fleshy, about 1/2 to 2-1/2 inches across, with scalloped or shallowly lobed edges and no hairs.
• Leaf stalks: Long, often several inches, and attached at the center of the leaf's underside so the blade sits like an umbrella.
• Flowers: Tiny white star-shaped flowers, each under 1/4 inch with five petals, grouped in umbrella-like clusters of about 5 to 10 at the top of a stalk, mostly in summer.
• Fruit: Small, round, flat dry fruits about 1 to 3 mm across that ripen in summer.
• Stems and rhizomes: Smooth, fleshy, creeping stems and rhizomes run along or just under the soil surface, forming dense mats.
• Habit: Low and prostrate, usually just a few inches tall in a mowed lawn.

Where it grows in the United States

Dollarweed is native to much of the southern, eastern and central United States as well as the Caribbean and Latin America, and USDA lists it as native to the lower 48 states, Canada and Puerto Rico. In North Carolina it grows in the Piedmont and Coastal Plain, and it is common throughout Louisiana. It is hardy across a wide range of climates, roughly USDA zones 4 through 10.

Its natural home is wet ground: swamps, moist open areas, roadside ditches, pond margins and shallow water, where it can float. In yards it moves into lawns with moist or wet soil, low spots, poorly drained areas and turf that is watered too often, and it does best where the grass is thin and weak. In ponds, dense mats can crowd out other plants and alter oxygen levels in the water.

Dollarweed look-alikes

A few plants get mixed up with it:

• Dichondra (Dichondra spp.): Also forms low mats of small, roundish leaves, but its leaf stalk attaches at the edge of the leaf rather than in the center. Check where the stalk meets the blade and you will know which one you have.
• Other pennyworts (Hydrocotyle americana and other Hydrocotyle spp.): NC State Extension notes dollarweed is often confused with Hydrocotyle americana, a close relative. Several pennyworts share the dollarweed name, and Extension lawn guides treat them together as one group with the same control approach.

How to get rid of dollarweed

Pulling, digging and mowing: In landscape beds, dig or pull dollarweed where practical and take the rhizomes with it, because pieces left behind regrow. Removal alone will not hold in a lawn unless the wet conditions are fixed too. Fill the bare spots left after removal with turfgrass plugs or sprigs so the gap does not fill back in with weeds, and keep a 3-inch layer of mulch around trees and shrubs to help keep it out of beds.

Cultural control matters most, because the right conditions keep it from coming back.

• Cut back irrigation first. Established lawns and landscapes generally need about an inch of water a week, and University of Florida research found that less frequent watering reduced dollarweed.
• Improve drainage in low, soggy areas for long-term control.
• Keep turf dense with the right mowing height, fertilizer based on a soil test, and proper soil pH for your grass.
• Keep the lawn free of stress from insects, disease, drought and nutrient problems so the grass can compete.
• Mulch around trees and shrubs about 3 inches deep.

Herbicides: Fix the watering first; herbicides alone will not keep up with a soggy lawn. In warm-season lawns, apply postemergence herbicides in late spring after full green-up, while dollarweed is small, because control drops as plants mature. LSU AgCenter names metsulfuron as the most effective active ingredient for dollarweed, though repeats may be needed. Other options include atrazine (St. Augustinegrass and centipedegrass, ideally fall and late spring), three-way products with 2,4-D, dicamba and MCPP or MCPA, combinations that add carfentrazone, imazaquin (not for tall fescue), and thiencarbazone with iodosulfuron and dicamba. St. Augustinegrass and centipedegrass are more sensitive to 2,4-D, so follow the label for those grasses, and avoid most treatments during spring green-up or above 90°F. Atrazine and imazaquin can reach groundwater, so do not use them on sandy soil over a shallow water table. In beds, spot-treat with glyphosate while shielding ornamentals, or use imazaquin only around plants on its label. Use products labeled for your site, and follow the label, which is the law. If you hire someone to spray, make sure they hold your state’s pesticide applicator license; the rules for each state are in our pesticide applicator license guide.

Keeping it from coming back

Dollarweed is mostly a symptom of too much water. Review your irrigation so established turf gets roughly an inch a week rather than frequent light sprinklings, and correct drainage where water sits after rain.

Then keep the turf strong: mow at the proper height, fertilize by soil test, repair bare areas promptly with plugs, sprigs or sod, and keep mulch around trees and shrubs so it does not creep into beds.

Questions we get about dollarweed

Similar weeds

DichondraDichondra carolinensisBurcloverMedicago polymorphaChamberbitterPhyllanthus urinaria