Oxalis is a spreading ground cover that is often called a shamrock plant because of its clover-like leaves. Oxalis produces small, pink or yellow flowers during the growing season, which is the spring and summer in Texas. There is a native variety in Texas called creeping oxalis (Oxalis corniculata L.) that is often considered a weedy pest in Texas lawns. However, for landscaping purposes, large-flowered pink sorrel (Oxalis debilis) is the type most often grown.
Locate a well-drained area in the landscape that receives dappled shade and remains moist during the day. If growing oxalis in a container, place the container under a shade tree or arbor with dappled shade.
Plant oxalis plants about 6 inches apart in a checkerboard fashion to get eventual coverage if you are using oxalis as a ground cover. Oxalis produces small bulbs that can be easily pulled apart by hand to make individual plants. Plant each bulb about 1 inch below the surface of the soil. The bulbs can be planted anytime, but early fall is the best time to plant the bulbs in Texas. If growing from seed, start seed indoors in a warm area (60 to 75 degrees Fahrenheit) in early fall or early spring. Plant oxalis seed just under the surface of the soil and keep the soil moist, but not wet, until the seeds sprout in two to eight weeks. Water as needed to keep plants actively growing.
Cover the outside planting area with 1/2 inch of mulch to conserve moisture. Water frequently to keep oxalis plants actively growing. Fertilize with any commercial balanced garden fertilizer, if desired; if you have average garden soil, fertilizer is not needed.