Oxalis (O. corniculata) is a broadleaf, perennial weed with pale green, clover-like leaves divided into three heart-shaped leaflets. Small, bright yellow, five-petaled flowers can appear year round, but form mostly in spring. Oxalis can grow 4 to 12 inches tall and spreads rapidly by seed and rooting stems. Stems are covered with thin, fine hairs. Oxalis is also called False Shamrock and Sourgrass.
The weed thrives in a wide range of conditions, including moist, well-fertilized lawns or in dry, open spaces. A similar species of Oxalis, or Bermuda Buttercup (O. pes-caprae), is sometimes found in shady areas of cooler climates. It is taller and more upright, and spreads by small underground bulblets. The leaves are often spotted purple. It is very difficult to control.
Oxalis is found throughout the United States.
Related or Similar Plants
Shamrocks, Sourgrass, O. pes-caprae, Bermuda Buttercup, Clover.