Purslane cultivars produce more and larger flowers than their wild cousins.
Use purslane cultivars in hot sunny places where little else will grow. They are especially pretty when planted in containers where the brilliant flowers (but only when the sun is shining) and interesting foliage can colorfully cascade over the sides.
Purslane is a little sprawling annual that trails along the ground forming mats of reddish green semi-succulent stems and leaves. About an inch (2.5 cm) long, the soft, fleshy leaves are spatulate or obovate in shape, and arranged alternately along the stems. The bright yellow cup-shaped flowers are about a half inch (10 mm) or less across, borne on short erect stems, and subtended by a cluster of modified leaves called an involucre. The flowers have five petals and, although small, are rather showy, looking a lot like miniature rose flowers. Purslane flowers open in the sunshine and close up in the shade. They do not open on cloudy days. If you touch the stamens, they start moving back and forth, probably expecting to dust visiting insects with pollen.
Kitchen garden purslane (P. oleracea var. sativa) is larger with thicker stems and is very succulent. It is cultivated for food in many parts of the Old World. ‘Giganthes’ has double bright yellow flowers an inch (2.5 cm) in diameter. Other cultivars with flowers that are larger and showier than the species, are becoming widely available.
Purslane is believed to have originated in India, but has escaped wide spread cultivation and become a weedy cosmopolitan immigrant, especially where summers are fairly warm and the soil is dry. Purslane now occurs in each of the United States except Alaska, and in much of Europe, Asia, North Africa and Australia. In many places, purslane is considered a weed. Most Americans know it as a summertime weed in suburban lawns.
Purslane is easy to grow in the ground or in a pot as long as the soil is dry and well drained, and it gets full sun. Light: Purslane should get full sun. The flowers open only when the sun shines. Moisture: This is a plant of dry areas and needs only occasional watering. Be sure the planting medium is very well drained. Hardiness: USDA Zones 9-11. Purslane is an annual that can survive outside year around only in the nearly frost-free zones. In zones 7-8 it can be started outside from seed after the chance of frost has past. In cooler climates, it should be started indoors before setting out in late spring.
Propagation: Purslane is easy to propagate with stem and leaf cuttings inserted shallowly into the potting medium. It also is easy to grow from seed sown in situ in spring.
Flowers of both the purslane cultivars and those in the wild are closed at night and on cloudy days, opening only when the sun is shining.
Rugged purslane endures hot sun, drought and pollution to thrive in the curbside crack of a busy highway.
Purslane is often grown in the annual flower garden as a low growing filler or border edge. It is well suited to rock gardens. Purslane is excellent in hanging containers and window boxes where can trail over the sides.
Purslane is widely cultivated (and even more widely harvested from the wild) for use raw as a salad green, cooked as a pot herb, as a thickener in soups and stews, and in stir-fry dishes. It has a high vitamin C content, is rich in iron and has a very high concentration of omega-3 fatty acids. Purslane is an important vegetable in Indian, Greek and Middle Eastern cuisine. The leaves can be harvested within two months after sowing seed, and the plant continues to produce new leaves until frost.
Purslane has been used topically for the treatment of skin rashes and insect bites.
There are more than 100 species of Portulaca, but very few are cultivated. Portulaca grandiflora (rose moss) and its hybrids and cultivars are perhaps the most popular and the showiest of the purslanes. Rose moss has cylindrical leaves and comes with single or double flowers an inch (2.5 cm) or more across in many different colors. Some even have striped flowers.
Purslane is often an annoying weed, but apparently Arizona is the only U.S. state that prohibits its cultivation and sale.