Erica cameronii L.Bolus
Common names: Hex River heath, Cameron heath, crimson heath (Eng.); heksrivierheide (Afr.)
Erica cameronii is a strikingly beautiful, rock-dwelling species, limited to high altitudes in the Hex River Mountains. One particular shrub known amongst mountaineers as the ‘Old Man’, grows amongst large boulders high on the Fonteintjiesberg, and has spread to over 5 sq. m.
Erica cameronii is a prostrate, woody shrub, typically growing to a metre in diameter, although plants in areas protected from fire, may develop into much larger plants. It forms dense, multi-branched mats spreading against boulders, with older specimens producing a thick, woody, tree-like trunk.
The leaves are dark green and closely arranged.
It displays very attractive urn-shaped, crimson-red flowers, covered in small, glandular hairs. The flowers are arranged in clusters of three and appear from November to January.
Erica cameronii is currently Red listed as LC (Least Concern), because its population is stable and not threatened.
Distribution and habitat
Erica cameronii occurs high on the rugged Hex River Mountains between Worcester and Ceres in the Western Cape. It is found growing amongst boulders, rocky outcrops and on mountain peaks between 1 500 and 2 000 m. At these altitudes it is subject to cold, wet winters with periodic snow and ice and relatively cool conditions in summer. Even though these mountains are a little further from the coast, they are often covered by moist, southeasterly clouds during the hot summer months. These clouds cloak the higher peaks condensing out to provide some summer moisture to tide the vegetation through the long dry seasons.
Derivation of name and historical aspects
Erica cameronii was named after Mr Ken Cameron, who was a pioneer of mountaineering in the Cape. He discovered the species while walking in the Waaihoek Mountains.
Erica cameronii is a rocky species in rocky scree fire refugia where it escapes or survives fires due to its protected habitat amongst boulders and by a special adaptation to fire. The vegetation at the high altitudes where it grows, is low or sparse and therefore, does not support intense hot fires. Therefore, when this species is burnt, it often survives, because it has a thick, woody stem emerging from between rocks or out of crevices, from which it can resprout.
The term whereby plants that survive fire by having buds beneath thick, protective bark of a trunk or stems is ‘epicormic resprouting’. Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up the plant. Under certain conditions, they develop into active shoots, such as when damage occurs to higher parts of the plant from fire or light levels are increased following removal of nearby plants. A good example of an epicormic resprouter is Protea nitida.
It is suggested that this erica survives icy conditions because it hugs boulders and spreads over the ground to benefit from the little warmth coming from the earth. It has been noticed that when covered with snow or ice, the rocks or earth exudes sufficient warmth to cause enough melting to create a protected space between these surfaces and the snow or ice. This gap-area forms under the protective cloak of snow-ice, allowing plants, such as the erica and even restio seedlings, to survive the freezing temperatures.
Erica cameronii is probably pollinated by orange-breasted sunbirds because its bright red flower colour is associated with bird pollination. Also, these birds have been recorded at high altitude foraging Protea scolopendrifolia on nearby mountain ranges. Bird pollination is further supported because the habit and habitat of Erica cameronii—gnarled plants with urn-shaped flowers sprawling over rocks on mountain cliffs and summits is similar to E. halicacaba, which is pollinated by birds. Sunbirds, insert their beaks into the corolla tube to feed on the nectar at its base, and in so doing, come into contact with the pollen and stigma, and pollinate the flowers.
Most plants growing at high altitudes in the Cape Mountains flower in summer because the warmer growing season is shorter than at lower altitudes. Erica cameronii and many other erica species occurring on high mountains, flower in summer.
Erica cameronii has no known medicinal uses. It is very attractive collector’s plant, but slow growing with the advantage of being long lasting for erica.
Growing Erica cameronii
Erica cameronii should be grown in containers because, typical of many high altitude species, it does not adapt well to average garden conditions. Having said this, it is not a difficult plant to grow in pots, and a collection by Kirstenbosch National Botanical Garden staff made in 1972, still grows well to this day.
This species should kept under 40% shade or where it only receives partial day sun, but good light conditions, to replicate cooler environment it comes from. Be careful not to expose this species to a long afternoon of baking summer sun.
Seed germinates the same as most other erica seed, but it is almost impossible to obtain. Seed has been harvested from Kirstenbosch plants, by artificially pollinating the plant with a small paint brush. Should seed become available, sow it in late summer or autumn. Treating the seed with Instant Smoke Plus Seed Primer, improves germination. Use a well-drained, sandy, slightly acidic medium. The seed is small and must only be lightly covered. Use a fine gentle spray when watering and keep the trays moist and warm. Seed germinates in about six weeks and the young seedlings are very tiny and delicate. Prick them out into small grow plugs when they are 1 cm tall. Feed weekly with a dilute organic fertilizer. Pot the young plant out, when they have filled the container. The recommended pot size for a mature specimen of this species should be about 25 to 30 cm in diameter.
Erica cameronii can be propagated from cuttings taken in autumn or spring. It is difficult to find suitably thin new growth from such a woody species. Look for cuttings within the plants branch structure, where the material is a little etiolated and softer. Take 20–30 mm long, semi-hard wood heel or stem cuttings and remove the leaves from the lower third of the cutting. Dip the base of the cutting into a rooting hormone for semi-hardwood cuttings and place into a tray filled with 50% peat, or milled pine bark, and 50% perlite. Place the trays in a propagation unit with overhead mist and bottom heating of between 22–24°C. Once the cuttings are rooted, pot them up into small plugs in multi-trays or ½ litre plastic bags. Young cuttings must be watered well and kept under shade.
Ericas are sensitive about soil. Use a well-drained growing medium consisting of a combination of river sand and well-decomposed pine bark in roughly equal proportions. The potting medium should be acidic, contain no manure and have low levels of phosphate with an optimum pH between 5 and 6.5.
- Baker, H.A. & Oliver, E.G.H. 1967. Ericas in southern Africa. Purnell & Sons, Cape Town.
- Manning, J. & Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: the Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.
- Schumann, D., Kirsten, G. & Oliver, E.G.H. 1992. Ericas of South Africa. Fernwood Press, Vlaeberg.
- Dr A. Rebelo, personal communication
- Ross Turner, personal communication
Kirstenbosch National Botanical Garden
Plant Type: Shrub
SA Distribution: Western Cape
Soil type: Sandy
Flowering season: Early Summer
Flower colour: Red
Aspect: Full Sun, Morning Sun (Semi Shade)
Gardening skill: Challenging