The Problem
Dollarweed (Hydrocotyle spp.) is a perennial broadleaf weed of turfgrass. It is also known as pennywort or marsh pennywort. Several important species include coastal plain pennywort (H. bonariensis), water or many-flowered pennywort (H. umbellata) and whorled pennywort (H. verticillata). All are aquatic dicot perennials with round, bright leaves that have ‘scalloped’ margins. The umbrella-like heads of small, white flowers also helps to distinguish this plant from most others. Dollarweed is a problem on coarse-textured lawns that remain wet. In low to medium maintenance lawn situations, dollarweed can out-compete St. Augustinegrass and centipedegrass.
What To Look For
Dollarweed has erect, long-stalked, rounded, bright green, shiny leaves with veins originating from the leaf center. The round leaves look like miniature lily pads and have scalloped margins (rounded teeth). The petiole in center of leaf appears “umbrella-like”. In summer, white flowers appear and are arranged as elongated spikes or as rounded umbels at the top of a long stalk. The fruit is greenish, rounded and somewhat flattened.
Dollarweed is typically found in moist to wet sites or anywhere moisture is in excess. Dollarweed produces seed, but also has rhizome and tuber plant parts that aid in its propagation. Dollarweed is native to North America and can be found from Maine, south into Florida, and west to Minnesota and Texas, Utah, Arizona and California.
The Solution
Cultural practices are the first step in reducing dollarweed.
- Adjust irrigation scheduling – Deep, infrequent irrigation can reduce dollarweed
- Maintain turf density with good fertility levels – Limits dollarweed spread via rhizomes
- Avoid scalping – Ensure correct height of cut, use 1/3 rule to determine frequency
- Timely management of disease – Large patch and take-all root rot create thin areas for weeds
Postemergence herbicides can be used to control dollarweed. Weeds are best controlled while young and actively growing.
Celsius® WG provides control of hard-to-control weeds such as dollarweed, and has safety on St. Augustinegrass, bermudagrass, zoysiagrass and centipedegrass. Celsius WG is broad spectrum and contains three active ingredients from two different modes-of-action. In addition to dollarweed, Celsius WG can control over 150 broadleaf and grassy weeds. Celsius® XTRA controls a broad spectrum of difficult broadleaf weeds like dollarweed, plus sedges and kyllingas. Tribute® Total is a broad-spectrum, postemergence herbicide that controls some of the most troublesome grassy and broadleaf weeds in warm-season turf.
Additional resources
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Solution sheet - Dollarweed |
