Problem: Oxalis (Lawns)
Oxalis stricta and O. corniculata Oxalis, also called yellow woodsorrel or creeping woodsorrel, is a perennial plant that thrives in dry, open places but may also be a problem in moist, well-fertilized lawns. It often invades lawns that are beginning to thin from insect, disease, or maintenance problems. Oxalis reproduces from the seeds formed in the seedpods. When the pods dry, a light touch causes them to explode, shooting their seeds several feet in all directions. Oxalis leaves contain oxalic acid, which makes them sour.
Check the soil pH level and follow recommended lawn care practices for a healthy, vigorous lawn. A healthy lawn helps smother the oxalis.