Oxalis acetosella (Shamrock)

Wood sorrel (Oxalis spp.) can be grown outdoors in rock gardens and as a ground-cover plant or indoors as a houseplant. It typically is hardy in U.S. Department of Agriculture plant hardiness zones 5 to 11; however, the more than 300 Oxalis species have some variation in hardiness. The species known as shamrock (Oxalis acetosella) is commonly grown as a houseplant. Wood sorrels generally grow to a height of 6 to 10 inches and can spread nearly indefinitely by underground runners. They usually bloom in spring and fall, producing pink, purple, red, white or yellow flowers.