Dollarweed (Hydrocotyle spp.), also known by the name pennywort, is a perennial weed that loves humid, warm environments. This weed can be easily identified by its leaves that are very similar in appearance to small lily pads with their shiny bright green color and wavy edges. Dollarweed is commonly spotted in St. Augustine lawns located along the coastline or near bodies of water, however, dollarweed also grows in other various grass types. Read on to discover how to control dollarweed.
Although dollarweed is commonly confused with a similar looking weed, dichondra, dollarweed can be distinguished by its stem growth: the dollarweed stem grows from the center of the leaf while the dichondra stem grows from the edge of the leaf.
Dollarweed grows close to the ground and spreads by tubers, rhizomes and seeds. Unfortunately, it can multiply quickly throughout your lawn as it will form roots and create new plants wherever the nodes of its creeping stems touch the soil. This weed also develops small flowers that are white and bloom from July to August.
Pictured above from left to right: Dollarweed stem growing from the center of the leaf and dichondra stem growing from the edge of the leaf.
Pictured above from left to right: Dollarweed growing in moist environments and dollarweed flowers.
Dollarweed Non-Chemical Control
To begin with dollarweed control, a few various cultural controls can be implemented to limit the favorable conditions that allow the weed to thrive. Dollarweed loves water and flourishes in conditions with overly moist soil—in fact, it can even continue to grow and will float in an abundance of water. Ensuring that your lawn isn’t too moist can keep dollarweed from being able to grow and spread; therefore, reducing irrigation frequency can be very effective, especially in areas that have poor drainage. Check out our irrigation guide to learn more or consider conducting a simple irrigation audit.
Dollarweed has a better chance of growing in areas that are mowed too short. Mowing at the proper height allows the grass to develop a healthy root system and a thick stand of turf that can keep weeds from developing or spreading. Be sure to mow your lawn at the specific height your grass type performs best at. Learn more in our lawn mowing guide.
Finally, proper fertilization of the lawn can help it develop a healthy canopy that is thick enough to crowd out weeds. Here are some of our favorite fertilizers. You can learn more about them in Why Use Lawnifi Fertilizer?.
This weed can be difficult to pull by hand as a large part of the plant is found underground and can be left behind. Overtime, the parts of the plant located underground will repopulate. If the issue is small and isolated to one area, you can try to hand pull it carefully and thoroughly. If the problem is large, this may be too difficult.
Dollarweed Chemical Control
Chemical dollarweed control products can be effective against dollarweed and both pre- and post-emergent herbicide options are available. A pre-emergent, as its name suggests, controls weeds before they germinate and appear in your lawn. Post-emergents, on the other hand, are products that control currently existing weeds.
Pre-Emergent Control of Dollarweed
A product that offers both pre- and post-emergent control is Hi-Yield Atrazine (active ingredient: Atrazine). Hi-Yield Atrazine can be mixed in a tank and applied to the entire lawn or to problem areas during either the growing or dormant season. This product is the best dollarweed killer for St. Augustine and centipede lawns. Hi-Yield Atrazine is typically most effective when applied while weeds are small or before they have emerged if used as a pre-emergent.
Spectracide Weed Stop for St. Augustine and Centipede Lawns is also a great pre- and post-emergent control product for dollarweed as its active ingredient is also Atrazine. However, Spectracide Weed Stop for St. Augustine and Centipede Lawns is a little easier to apply as it can be hooked to the end of a garden hose for an even spray application.
Hi-Yield Atrazine Weed Killer$16.95 – $19.95
Post-Emergent Control of Dollarweed
A few post-emergent options are listed below. Drive XLR8’s active ingredient is Quinclorac and it can be tank mixed with water for application. SpeedZone Broadleaf Herbicide includes 2,4-D, Dicamba and Mecroprop-P in its mixture, which is a great combination of active ingredients for broadleaf weeds such as dollarweed. Blindside includes Metsulfuro and Sulfentrazone and finally, Q4 Plus combines active ingredients 2,4-D, Dicamba, Quinclorac and Sulfentrazone to control dollarweed. Blindside, Q4 Plus and SpeedZone Broadleaf Herbicide can be tank mixed before application.
It should be noted that the above four products should not be applied on St. Augustine or centipede lawns as both grass types are sensitive to 2,4-D and other active ingredients. If you have a St. Augustine or centipede lawn, Atrazine-based weed control products are the best options.
Since dollarweed prefers a moist environment, there are many cultural controls that can be used to prevent its growth. If you need to turn to chemical controls it is essential to read the label carefully to ensure proper use and compatibility with your lawn. Chemical controls can cause damage to your lawn when they are used incorrectly.