Experts and BHG readers answer.
Sand burs in St. Augustine lawns
Use a weed preventer for lawns. Sand burs are annual weeds, and preventer in early spring should keep out most of them for the year (but you'll need to do it every spring). In Texas, you might be nearing the end of your window of opportunity, so do this ASAP.
Also make sure you mow our lawn high (like 3 inches), as this will make it harder for the burs to thrive.