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do dollar weeds have seeds that spread

Lawns: Dollarweed thrives in weak, thin turf with excessive moisture. The first defense against dollarweed is to reduce moisture levels and modify cultural methods (i.e., proper mowing height and irrigation). After taking steps to modify the lawn care techniques, a chemical control may still be necessary to further reduce the dollarweed population. Herbicides should be chosen according to turf species and applied in late spring (after full spring green-up of the lawn) when weeds are small. Herbicide effectiveness is reduced as weeds mature.

A properly maintained landscape that is not stressed by insects, diseases, drought or nutrient imbalance is the best defense against weeds. Proper mowing height of lawns and a 3-inch thick mulch layer around trees and shrubs will prevent the invasion of weeds. For more information on proper landscape maintenance techniques, see the following fact sheets: HGIC 1056, Watering Trees & Shrubs; HGIC 1604, Mulch; HGIC 1201, Fertilizing Lawns; HGIC 1205, Mowing Lawns and HGIC 1207, Watering Lawns.

Cultural Control

Joey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University

A three-way herbicide may be used safely on bermudagrass, zoysiagrass, centipedegrass, St. Augustinegrass, and tall fescue. The active ingredients of a three-way herbicide include the following broadleaf weed killers: 2,4- D, dicamba, and mecoprop (MCPP) or MCPA. Examples of three-way herbicides in homeowner sizes are:

Dollarweed is a water-loving plant that can float. The presence of dollarweed indicates that there is excessive moisture in the area. Research at the University of Florida demonstrated a reduction in dollarweed just by reducing irrigation frequency (

White vinegar has long been rumored to be a safe, effective weed killer, but it wasn’t until 2002 that U.S. Department of Agriculture scientists did a study on the effectiveness of using white vinegar on weeds. The Agricultural Research Service found that vinegar with concentrations of 5 percent and 10 percent acetic acid killed various weeds within two weeks, while vinegar with higher percentages of acetic acid killed the weeds within a couple of hours.

The acid in vinegar damages the leaves of weeds, drying them out and rendering them unable to make food. For this reason, the broader the leaves, the more effective the vinegar is likely to be. In the case of dollar weeds, the large, round leaves make it more likely that the vinegar will be effective. The major issue is the fact that dollar weeds like moisture and are found in wet places. You don’t want the moisture to wash the vinegar off of the leaves, so spray the weeds on a hot, dry day — the hotter, the better.

The dollar weed (Hydrocotyle vulgaris) thrives in wet, boggy areas. Although dollar weed is often grown as a pond plant, it frequently invades lawn turf and garden beds. Also called pennywort, the plant is invasive and difficult to eradicate. Although some home gardeners may be tempted to reach for chemicals to control the plant, use a nontoxic, organic weed killer made with white vinegar instead: It’s safer for your yard, your children and pets, and for the environment.

White Vinegar

Dollar weeds thrive in U.S. Department of Agriculture plant hardiness zones 6 through 10. A single plant can spread as much as 20 feet, and they can grow to heights of 6 inches. The plants creep along the ground in wet areas, in full sun, part shade or even full shade. They are best grown in containers to control the spread of the plant, warns the Missouri Botanical Garden website, and may even grow in as much as 2 inches of standing water.

Although you can spray the vinegar directly on the plant, consider making an even more effective weed killer by combining white vinegar with equally acidic lemon juice. The University of Washington Botanic Gardens recommends a solution composed of a quart of white vinegar combined with 4 ounces of lemon juice. Pour it into a spray bottle, and then use it to kill the dollar weeds. Be sure to protect your eyes and skin, however: Although the solution is nontoxic, it can still sting your eyes and irritate the skin.