Sour Clover Oxalis

Oxalis is a genus of annual or perennial plants that are native to North America, Central America, South America, Australia, Europe, as well as parts of Asia and Africa. They are usually found in woodlands, tropical areas, or in the higher elevations of the alpines. This genus has 582 accepted species and is a member of the wood sorrel family (Oxalidaceae). The genus name, Oxalis, is derived from the Greek word that means "sour." Many members of this family are grown for their pretty flowers and attractive leaves. Some are valued in the garden or as houseplants; however, some species can be problematic and tend to become weedy. Oxalis plants are generally long-stemmed, and their foliage may have 3 to 5 leaflets that resemble clover or butterfly wings. The leaves are open during the day but fold up at night. They are often grown as a houseplant or garden plant. They may be annual or perennial depending on your USDA Plant Hardiness Zone

Species of Oxalis prefer full sun to bright indirect light and moist, fertile, well-drained loamy soil with a slightly acidic pH. They like cooler temperatures ranging from 50 to 75 degrees Fahrenheit. The plants should be fertilized monthly during their growing season.  When planting, bury the rhizomes or stolons about 2 inches deep. Many of the plants become dormant during the summer after flowering is complete. Decrease watering the plant and removed any dead leaves as the plant becomes dormant. Place the plant in a dark, cool area and discontinue watering. New growth should emerge in 1 to 3 months. Once this occurs, the plant can be returned to a sunny location. The USDA Plant Hardiness Zones vary from 5 to 10 depending on the species. Some species are propagated by rhizomes and stolons, while others are propagated by division or seeds.  

The leaves are clover-shaped and may have 3 or 4 leaflets; however, some species have up to 9 leaflets. The color of the leaves can vary from green, red, or purple, or variegated. The flower color varies depending on the species and can range from white, yellow, purple, pink, or red. The flowers are borne on long stalks and are 5-petaled, and the fruit is a capsule. Some species grow from corms and have a mounding habit. Others have a creeping habit and spread by rhizomes. 

Oxalis can be used as a houseplant, container planting, hanging baskets, or in the garden. The most common species that are sold as houseplants are usually known as Shamrocks. They include the following species: Oxalis acetosella, Oxallis deppei, Oxalis purpurea,  Oxalis regnelii, and Oxalis triangularis. Around St. Patrick's Day, many of these plants are very popular and are easily found commercially.

Insects, Diseases, and Other Problems:  Plants in this genus have relatively few pests, but monitor for aphids, leaf miners, spider mites, and whiteflies. Fungal diseases such as mildew, leaf spots, or rust can occur. Overwatering can cause root rot and cause mushy stems and yellow leaves. Wilting of the leaves may be caused by underwatering or low humidity. Some species are very prolific and considered weeds. 

These plants are toxic if ingested. Keep these plants out of the reach of children and pets.