Rhodocoma fruticosa

(Thunb.) H.P.Linder

Family: Restionaceae
Common names:
kanet (Afr.)

Rhodocoma fruticosa

Rhodocoma fruticosa is a tough, water-wise restio, perfect to use in a dry fynbos garden.

Description
Rhodocoma fruticosa has an upright, arching habit and grows 1 m tall. The crown spreads to 1 m in diameter. This species has a clumped habit, meaning the underground rhizome gradually spreads outwards over time. It will however stay in a rounded shape and does not form long runners. The diameter of plants at the base of the clump varies between 0.3–1 m.

Culm showing sheath

The attractive culms (stems) are unbranched and are a distinctive grey-green. In restios the leaves have been reduced to papery looking sheaths and each culm has a number of these along its length. Each sheath is 30–50 mm long and provides a nice contrast against the grey culm. As the sheaths age they fray a little along the tips but do not fall off.

Male inflorescence

The male inflorescence is the key in identifying this restio. The inflorescence is 60–200 mm long and contains many pendulous spikelets that have a distinctly elliptical shape.

Female inflorescence

Female inflorescences are upright and can vary in length from 35–300 mm. At flowering their styles, although small, are easy to spot. They occur in threes and are feathery and white. The ovary has 3 locules (compartments), and when the seeds are ripe it splits open shooting the seeds outwards.

Flowering occurs from April to July and seed is released in October and November. Seeds are brown or grey and 1–2 mm long.

Conservation status
Rhodocoma fruticosa is listed as Least Concern .

Distribution and habitat
Rhodocoma fruticosa has a very wide natural distribution and is one of the most common restios to be found amongst fynbos. It grows from Ceres in the Western Cape, spreading eastwards through the fynbos to the Eastern Cape and into KwaZulu-Natal on the Drakensberg Mountains.

Amongst the fynbos it grows along dry lower slopes on sandstone- and laterite-derived soils. In the Drakensberg it grows on middle altitude slopes. The altitude range varies from 0–2 300 m.

Derivation of name and historical aspects
The family name, Restionaceae, refers to the Latin restis , which means cord or rope. Restionaceae are found in the southern hemisphere with ± 357 species occurring in Africa, ±150 in Australia, 4 in New Zealand and 1 each in South America and South East Asia respectively.

Rhodocoma is a very small genus in the restio family containing 8 species. Other well-known members are R. gigantea and R. capensis.

Rhodo- originates from Greek and means rosy or red and –coma originates from kome (also Greek), meaning hair. The specific name fruticosa means shrubby or bushy. Both genus and specific name don't seem to make much sense, as plants are neither red nor bushy! The genus name could possibly refer to R. capensis which has rosy pink styles.

Ecology
Fynbos plants are adapted to grow and thrive in an environment exposed to fire in a regular cycle. Each species has developed its own survival strategy and Rhodocoma fruticosa is an example of a re-sprouter.

When fire sweeps through the veld this restio burns and is reduced to a blackened mound. This usually occurs during summer. It is not dead, as beneath the ground the rhizomes are protected. As soon as rain starts to fall, at the onset of winter, Rhodocoma fruticosa springs back to life vigorously sending up fresh new shoots from the underground rhizomes.

Uses and cultural aspects
Rhodocoma fruticosa has potential to be a useful landscaping plant suitable for various conditions, particularly dry fynbos.

Culms of Rhodocoma fruticosa

Growing Rhodocoma fruticosa

There are two ways to propagate restios: dividing the rhizome and sowing seed.

To divide plants, dig up an established specimen and cut the rhizome into big chunks making sure each piece has a good number of culms and roots attached. Plant these pieces into the ground or into pots and water them well. Do this task during late summer before the cool weather arrives when plants send up their new shoots. Plants will take at least a year to settle in and start growing strongly again.

At Kirstenbosch we primarily use seed propagation for the restio family. We find this a fast and easy method, allowing us to produce large quantities of plants each year. Members of the Rhodocoma genus are always the first of the restios to germinate, generally after about 1 week, and come up in profusion.

Sow your seed from April–May (autumn) when the days are warm (20–30°C) and the nights are cool (10–15°C). Treat seed prior to planting with Instant Smoke Primer. This smoke treatment vastly improves germination rates. Use seed trays that are 10 cm deep and fill these trays with a well-drained sandy medium. Scatter the seed uniformly over the medium, cover lightly with sand and water gently. Place the trays in a light, well-ventilated area. Keep the trays damp but not wet. Once the plants have developed a few small culms, after ± 6–12 weeks, and are 30 mm tall, they can be pricked out into 6-packs or plug trays. Use a well-drained fynbos potting medium. At Kirstenbosch we use 8 parts finely milled pine bark and 3 parts coarse gritty sand.

Harden off plants in a lightly shaded area until they are growing strongly (± 4 weeks) and then place in the sun. Once the roots start to show through the bottom of the trays, pot into small black bags to grow on further or plant directly into your garden.

You can plant into your garden at any stage during the year provided there is regular deep irrigation. The other option is to use natural rainfall to your advantage and plant at the beginning of the rainy season. Make sure soil is well drained and in a sunny spot. For the first year water well, allowing plants to settle in and send roots down deep into the soil. After this you can reduce watering to a good soak once a week.

In general, restios do not have any major pest or disease afflictions. The most common problem is damping off or fungal attack during seed propagation. Once plants are affected there is no cure, so prevention is the best option: treat with a general fungicide once a week commencing on sowing and use until pricking out.

References and further reading

  • Foden, W. & Potter, L. 2005. Rhodocoma fruticosa (Thunb.) H.P.Linder. National Assessment: Red List of South African Plants version 2013.1.
  • Goldblatt, P. & Manning, J.C. 2000. Cape Plants. A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.
  • Haaksma, E.D. & Linder, H.P. 2012. Restios of the fynbos. Struik Nature, Cape Town.
  • Linder, H.P. 2011. African Restionaceae version 6 . CD. University of Zurich, Switzerland.

 

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Kirstenbosch National Botanical Garden

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