from January 2001
The Restionaceae is a plant family from the southern hemisphere that is closely allied to grasses and sedges. Their adaptability to the California climate, as well as their graceful texture and form, make these plants great additions to gardens and landscapes. Restios are dioecious -- meaning male and female flowers are borne on different plants, and sometimes these plants can be quite different in form. All of these plants are clump forming, putting up new (and often taller) culms every year until they reach mature size.
South Africa is a major center of distribution of these grasslike plants. Historically, some restios (Chondropetalum) have been used for thatching, and literature tells of the foliage of many species being used in brooms. As cut foliage they tend to be long lasting, and the fluffy ones, (Rhodocoma, Thamnocortus), provide fine texture and support for flower arrangements.Most Restios grow best in full sun, in reasonably drained soils. They prosper in soils of low fertility, and are adaptable to situations with moderate to occasional summer water. Like many plants from South Africa and Australia, they are not tolerant of phosphorus in fertilizers. Hardiness varies.
Chondropetalum tectorum is probably the best known of the group, and has been grown in California since at least the early 1980's. It forms strong, dark green upright clumps to about 5' high that have been compared to unbranched Equisetum, though they do not have the root-wandering habit of that group. The new growth on the smooth round stems has dark brown bracts, which show their silky golden undersides as they fall from the stems. Flower spikes appear at the tips of the stems and are blackish brown. The form of the male and female plants and flowers is quite similar. This species has withstood frosts of 20 degrees, showing no damage. Plants grown in part shade, or with abundant water can be more lax in form. In South Africa, C. tectorum grows in seasonally wet soil. It was traditionally used as a thatching reed in South Africa for many years, though at present other species are more widely used for that purpose.
Elegia capensis can form clumps to 8' high and wide, though it takes some time to develop. The stems resemble giant branched horsetails with large golden bracts. Texturally a large clump assumes a very fluffy, somewhat undulating appearance. In nature, these are plants of marshy places and found along streams, so regular to moderate watering is needed. Golden brown flowers are carried at the tops of the stems, and are not particularly striking. Winter temperatures of 20 degrees brought real damage to the foliage of established clumps of this species in 1998, but all clumps resprouted in the spring, quickly regaining stature and mass. The new shoots on this species are especially striking.
Ischyrolepis subverticillata is more tolerant of shady situations than most restios. In South Africa it is found along streams from sea level to the lower mountain slopes. It makes vase shaped, medium green clumps to 5' with branched culms. Its rigid stems are more airy than Elegia capensis, though with the same "branched horse-tail" quality. Male and female flowers are borne on the tips of the branchlets. Winter temperatures of 20 degrees killed the foliage to the ground, but the plants have slowly recovered.
Restio tetraphyllus is native to Australia. Its bright green stems have the usual plume-like branches, and form loose mounds to 3-4'. Stems can drape to the ground creating a rounded profile for the clump. This plant is often recommended for poolside plantings, and grows best with regular to moderate water.
Valued for its fluffy, bright green stems, Rhodocoma gigantea makes a very dense feathery mass to 4' high by 3-4' wide. Flower stems rise from this foliage mass, and both male and female flowers have their charm. The male stems can rise to 8'+, and carry many dangling dark brown spikelets. Female flowers are on thin 2' stems, and when the female flowers mature they extend their delicate pink styles out to catch pollen. Flower stems rise in the winter months, and are striking until the flowers actually mature in spring. The very cold nights of December 1998 (20 degrees) burned the foliage to a very attractive burnt orange color, but the plants recovered quickly the following spring with new shoots. R. gigantea grows best in sun, and tolerates moist to moderately dry soil.
Thamnocortus cinereus is a more unusual, very erect, clump-forming restio. Foliage is feathery and bright green, but with silvery hairs on young growth that give an interesting texture to the foliage. Stems are greyish green and grow in a slightly zig-zag fashion. Flower stems rise well above the clump, and have a silvery cast. Male flowers are in hanging clusters, and female flowers are held on shorter stems. This is a species that grows on well drained soils in mountainous areas in nature.
Similar to the preceding species, Thamnocortus rigidus forms a very feathery foliage mass. The zig-zag sterile stems of the species are stiffer in appearance, and there are no silvery hairs. In nature it forms dense tussocks to 3', and the flowers are carried over the foliage. Male flowers should be in the usual dangling spikelets.
Restios seem at their prime in the winter garden, though they keep fresh foliage and sculptural form in all seasons. New growth commences with fall rains, and unexpanded shoots (for the fluffy ones) present a nice contrast for a while. Flowering generally begins in winter and can continue through spring. As a group these plants need little shaping or removal of dead stems. Foliage is long lasting and older foliage is usually overtaken by new growth. Tough, flexible stems on most species aid in their adaptability to windy sites.
Few groups of plants combine such unusual form and texture with such durability in the landscape. Whether grown for their sculptural form, cut foliage, or naturalized on occasionally watered banks, this is an exciting group of plants.