Q: I have a weed that appears to be taking over my St. Augustine lawn. It seems to be born bearing seeds. Can you tell me what it is? Plus I was told to add lime to my yard to get control my weeds. Will that really work?
A: The weed you brought to my office is called Chamberbitter (Phyllanthus urinaria L.) . You described it accurately when you said is is born with seeds. If you check under the stems you will locate dozens of seeds. It is classified as a summer annual and is found throughout Alabama, Georgia, Florida and Texas. It is native to Asia and found commonly in the tropics. I obtain a great deal of personal satisfaction from pulling these out by hand to ensure the seeds will be destroyed.
Regarding adding lime to control the weeds, we have no evidence this practice does anything to control weeds. Lime is added to raise the soil pH and I would only advise you to add lime if a soil analysis indicated a true need. Once lime is added and the soil pH is raised, it is very difficult to adjust or lower the pH.
The pH is an indicator of your soil acidity and determines how nutrients are absorbed through the root system to the plant. If the pH is too high or too low your grass can develop problems. Most St. Augustine grass prefers a pH of 6.5 so we will need to test your soil before we decide on the next course of action. Remember to take care of your grass by mowing grass at highest height, water only as needed, fertilize with 15-0-15 or 16-4-8 two to four times a year, and avoid using weed and feed products.