This is one of the most versatile plants of the large Cape reed family. It can be planted in the garden but will also do well in a pot on a patio or on a terrace. As a garden plant it is a low maintenance, elegant foliage plant that can grow in partial shade, half shade or in the full sun.

Ischyrolepis subverticillata is a tufted reed-like plant up to 2 metres high and up to 1.5 m in diameter. It has a very distinctive growth form with cane-like stems, which have soft green whorls of modified branches at each node. Male and female flowers are produced on separate plants, the female flowers are white, the male flowers greenish-yellow and quite insignificant. The pretty silvery seeds ripen in small capsules and it is at this stage that the female plant is at its best for use as cut-foliage, with tall arching stems and nearly black capsules at the end of each dark green whorl of foliage. The flowering time is during March or April and the seed is ripe in November, while the main growth flush is from August to January. As all restios, the plants are wind pollinated, although the bees have a few days during the flowering season when they are busy harvesting the pollen from the male plants.

In nature the plants can be found on Table Mountain sandstone bedrock in mountain valleys in the South Western Cape, from Caledon to Paarl. They typically occur along streamlines or along the margins of the riverine scrub-forest, where they receive some groundwater throughout the year. It is a common species in its relatively small distribution area. This restio has two survival mechanisms for existence in the fire-prone fynbos. It produces a large amount of viable seeds to be stored in the soil and it coppices from the rhizome or base after a fire.

The family name of Restionaceae refers to the Latin restis, which means cord or rope and alludes to the use of the plants in southern Africa. The more than 400 species in about 40 genera of the Restionaceae family occur in the winter-rainfall regions of South Africa and Australia, with outliers in Africa, Madagascar, Indo-China and Chile. The species name of subverticillata is from the Latin verticillata and means somewhat (sub) whorled, referring to the branches, which appear in poorly defined whorls at each node. The economic use of plants of this family has been limited, as the plants contain a large amount of tannin and so are grazed only as a last resort by cattle and sheep. The species that have simple unbranched stems are sometimes used for thatching, while the species with branched stems are used as brooms, in Afrikaans besems.

Growing Ischyrolepis subverticillata

This restio has been cultivated overseas under a variety of names for more than a century. It has been grown outside in protected situations in the milder climates of Ireland and Cornwall as well as in pots which were placed inside during the winter. In South Africa it can be grown in gardens in informal drifts or as a pot plant on a patio or terrace.

The plants are best grown from seed, which has a good germination percentage and germinates even better if treated with smoke or 'Instant Smoke Plus' seed primer. This species can grow in full sun, partial- or half shade and prefers a well-drained soil and plenty of air movement. The plants adapt to a large variety of soil types. The best time for planting restios is at the beginning of the rainy season, as the plants need regular watering during the first six weeks to two months after planting. After this initial period the plants can survive with a little additional watering but grow better with a normal garden watering regime. They may be fed with standard organic fertilizers such as Seagro or Kelpak, or by sprinkling the surrounding soil with a small amount of ammonium sulfate during the growing season. Restios will respond to regular watering by showing more robust growth, but they are essentially plants, which are adapted to a long dry season.

This is a fast growing species that will reach about 1 m high one year after sowing and will have formed a handsome plant three years after sowing. The plants produce a new growth flush in the centre of the plant every year. The individual stems start to deteriorate during the third year, but by that time already two new flushes of growth will have appeared for the yearly renewal of the plant. This governs the maintenance of the plant, which really only needs a regular removal of the brown, dead stems at the outside part of the plant.

References

• Andrews, S. & McClintock, D. (1982), Notes on Restio suberticellatus, The Plantsman 37:230-233.
• Dorrat-Haaksma, E. & Linder, H. P., 2000, Restios of the Fynbos, The Botanical Society of South Africa.
• Linder, H.P., 1985, A conspectus of the African Species of Restionaceae. Bothalia 15 : 3-4.
• Linder, H.P., 1991, A review of the Southern African Restionaceae, Contributions from the Bolus Herbarium, Number 13.
• Brown, N. Jamieson, H. & Botha, P., 1998, Grow Restios, Kirstenbosch Gardening Series, National Botanical Institute, Cape Town.

Hanneke Jamieson
Kirstenbosch NBG
March 2002