Dollarweed is thought of by some people as being the worst weed problem within St. Augustine grasses. This is largely due to the fact that Dollarweed and St. Augustine sod are perennial plants that thrive in the same type of soil and climate conditions. It is especially an issue in warm weather months, and many people will see this annoying plant popping up in the Spring, especially after a good rain. Given the opportunity, they can easily take over your St. Augustine lawn. Listed below are a few ways to nip your problem in the bud.
1.) Mow your lawn to the proper height. You can refer to our post about height requirements in your Florida lawn for helpful info on that subject here: http://southernsodservices.com/blog/2012/03/27/mowing-height-is-more-important-than-you-think/ A lawn at it's optimal height is a healthy lawn.
2.) Don't overwater. Dollarweed thrives in moist soil, so overwatering will excacerbate the issue. Due to research on the subject done by the University of Florida and experience in the field, most lawncare professionals believe that St. Augustine is overwatered by most home owners, and recommend giving your lawn one inch of water only when the blades of grass begin to wilt. You will then what to wait to irrigate until each time your lawn begins to wilt. To be sure you're giving that amount, you can put out a pie plate in your lawn, run your sprinkler cycle, and measure how much water is in the plate. This will let you know if your irrigation is too long or too short and you can adjust accordingly.
We reccommend that anyone with a St. Augustine lawn has a professional spray service that comes regularly to care for your lawn. They can see issues that may be arising in your lawn and can treat the problem before it gets out of hand. These professionals are well versed in safety and application of these chemicals. If you do decide to handle this on your own, you'll want to treat your St. Augustine lawn with an atrazine herbicidal formula in the fall to kill the Dollarweed seeds. Repeat the application in late spring to eliminate Dollarweed seedlings. As always when dealing with potentially toxic chemicals, please follow the manufacturer's use instructions for the chemical formulation you select and carefully read the label.
We hope these tips help as you care for your Southern Sod lawn!
Dollarweed, also known as Pennywort (Hydrocotyle spp.)