Erica unicolor subsp. georgensis
Erica unicolor J.C.Wendl. subsp. georgensis E.G.H.Oliv. & I.M.Oliv.
Common names: George onecolour heath (Eng.)
This shrubby heath produces clusters of red, tubular flowers with light yellow tips, which make it very eye-catching when reaching its flowering peak in spring and summer.
Erica unicolor subsp. georgensis is an evergreen, much-branched, single stemmed shrub, that grows about 1.3 m high. The leaves appear in fours and are more concentrated near the tips of the stems. They are short, 7–11 mm long, straight and narrow, often appearing to curve inwards and the margins are rolled or folded under, pale green when young and maturing to dark green, hairless and sparsely ciliate.
The shiny flower tube is hairless and has a sticky feel to it; the tubes are often straight or marginally curved. They are shades of pink to red with green or yellow tips. Sepals are about 11 mm long.
Erica unicolor is closely related to other tubular Erica species in the southern Cape, such as E. versicolor, E. diaphana and E. discolor and can easily be confused with them, however, E. unicolor has leaves and flowers in bunches of 4 (4-nate) and E. discolor and E. diaphana are 3-nate.
Erica unicolor subsp. georgensis has a conservation status of Rare. Its natural habitat in the mountains above George has been altered by agricultural practices and other developments, such as forestry. However, subpopulations occur within protected mountain areas, thus, although it is a range-restricted species that may have lost some of its habitat, it is protected and not threatened.
Distribution and habitat
This plant has established itself in the sandstone fynbos environment in the Outeniqua Mountains, in the southern Cape. It loves to grow in loamy and peaty, enriched soils. The climate is Mediterranean, with cold, wet winters and hot dry summers, although the southern Cape receives rain throughout the year.
Derivation of name and historical aspects
The genus name Erica is derived from the Greek word ereiko, which means ‘to break’ or ‘rend’; this could refer to the stems of the plant that are not very tough and break or tear easily. In turn ereiko is the Latin word for heath or broom. The specific epithet unicolor, which means ‘one colour’, refers to the flower colour, although the tips of the corolla shows a different colour it refers to the type species E. unicolor subsp. unicolor which has uniformly yellow flower tubes. This subspecies is named after the town of George, in the Western Cape, because its natural habitat is in the mountains around George.
The genus Erica comprises of about 860 species of which about 690 are endemic to the southwestern tip of South Africa. Ericas are one of the most important groups of plants of fynbos vegetation. The occurrence of heaths in East Africa, the Mediterranean and Europe represent low numbers of species, about 28 species collectively. Heaths are quite adaptable to a variety of habitats, such as coastal headlands, in a rocky terrain, in boggy swamps, open flats along streams, to high mountain peaks.
The genus Calluna was previously included in Erica; Calluna has much smaller leaves than Erica (less than 3 mm long) and the corolla displaying separate petals.
The species Erica discolor, E. versicolor, E. unicolor and E. diaphana (species with narrow flower tubes) are very similar and very difficult to distinguish from one another because of significant variation in their organs, and E. discolor was observed by botanists to vary from area to area. However, these 4 common and widespread species were retained by botanists because of the confusion in the group and 2 new species E. croceovirens and E. prolata were recently described.
This species is known to be pollinated by sunbirds. The sunbird uses its long curved beak to obtain nectar from the one flower and moves to the next flower; this action simultaneously carries pollen from the one flower to the other and plays a major role in completing the pollination process.
It regenerates readily from seed, which is produced in abundance. In general, the seeds of heaths are very small and stay viable for many years in the soil seedbank.
Erica unicolor subsp. georgensis is an attractive species which is very popular among garden enthusiasts; it produces flowers over a long period and is a good cut flower. It also grows well in pots and benefits from regular pruning. Ericas grow naturally well alongside members of the Restionaceae family and other groups of fynbos plants, such as members of the Rutaceae and Proteaceae, which also make ideal companions in the garden.
Growing Erica unicolor subsp. georgensis
Ericas grow well in nutrient-poor soils, with good drainage and a pH between 5.5 and 6.7, however, a regular feeding with an organic fertiliser at low concentrations proves to be beneficial. Well-rotted compost can be applied as mulch in the garden beds. Ericas perform optimally when their roots are not being disturbed; disturbing the roots is one of the major contributors that leads to plant shock and death.
Regular pruning after flowering and feeding is important to encourage new growth. Ericas are relatively short-lived fynbos plants and survive on average up to between 10 and 15 years, after which they need to be replaced. Dead wood should also be removed during the pruning process, to prevent the spreading of disease.
Take cuttings in autumn, spring or early summer. Remove some leaves from the lower part of the cutting and place the cuttings in a rooting medium made up of equal parts fine bark and polystyrene chips. Heel cuttings from thin, actively growing side shoots, respond more positively when it comes to root development. Apply a rooting hormone for semi-hardwood to speed up the rooting process, which can take up to 8 weeks before signs of rooting. The cuttings develop best when good air circulation is maintained. Good air circulation is important as it reduces fungal infections. A specialised facility, such as a propagation unit with heated benches and a misting system, is often best to successfully propagate this plant by cuttings. Cuttings can be planted into small pots when rooted with a mixture of 8 parts bark and 3 parts sand. Feed every 2 weeks with an organic liquid fertiliser.
Erica unicolor subsp. georgensis is best propagated from seeds. Soak the seeds overnight in a smoke extract (usually obtained from burning fynbos plant material). This will speed up the germination process. Sow seeds in seed trays (not less than 100 mm deep) filled with 1 part river sand and 1 part sifted composted bark, in autumn. The seeds are very small and need to be mixed with fine river sand prior to sowing, in order to obtain a more even spread of the seeds. This will also prevent or at least reduce damping off, which is a result of the seedlings developing too close together. Treat the mixture with a fungicide and keep the medium moist by watering with a fine hose. Place the trays in a warm and sheltered spot to encourage the germination process. The seeds show signs of germination after 6–10 weeks.
Provide young seedlings with good light and aeration. Seedlings can be planted out into small pots as soon as they are about 10 mm high. Thereafter, plant the plants in garden beds as soon as they reach ± 100 mm tall.
- 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.
- Oliver, E.G.H. & Oliver, I.M. 2002. The genus Erica (Ericaceae) in southern Africa: taxonomic notes 1. Bothalia. 32 (1). doi:10.4102/abc.v32i1.461.
- Oliver, E.G.H. & Oliver, I.M. 2005. The genus Erica (Ericaceae) in southern Africa: taxonomic notes 1. Bothalia 32: 46.
- Rourke. J.P. 1980. Wild flowers of South Africa. C. Struik Publishers, Cape Town.
- Schumann, D., Kirsten, G. & Oliver, E.G.H. 1992. Ericas of South Africa. Fernwood Press, Vlaeberg.
- Trinder-Smith, T.H. 2006. Wild flowers of the Table Mountain National Park. Botanical Society, Cape Town.
- Vlok, J. & Schutte-Vlok, A. 2010. Plants of the Klein Karoo. Umdaus Press, Hatfield, Pretoria.
- Von Staden, L. 2011. Erica unicolor J.C.Wendl. subsp. georgensis E.G.H.Oliv. & I.M.Oliv. National Assessment: Red List of South African plants version 2020.1. Accessed on 2020/11/06.
Kirstenbosch National Botanical Garden
Plant Type: Shrub
SA Distribution: Western Cape
Soil type: Sandy, Loam
Flowering season: Spring, Early Summer, Late Summer
Flower colour: Green, Red, Yellow
Aspect: Full Sun
Gardening skill: Easy