Moraea aristata is a beautiful late winter- and spring-flowering peacock moraea with white blooms marked with light to deep iridescent blue eyes or nectar guides. Although critically endangered in the wild, it is easily cultivated in sandy or clay soils in full sun in deep containers, dedicated rock garden pockets, or even naturalised in buffalo grass.
Moraea aristata is a winter-growing, summer-dormant geophyte (a plant that grows from subterranean buds produced on specialised storage organs). It has a small hard corm that is annually replaced and consists of a short, solid, vertical stem surrounded by strong outer corm tunics. The mature plant reaches 20–35 cm high and produces a single long, linear, smooth basal leaf up to 40 cm long. The large, Iris -like flowers are unscented and borne at the tip of the main stem and occasionally on short side branches. The three large outer tepals are pure white or sometimes speckled or streaked with violet. They are attractively marked at their bases with iridescent light to dark blue nectar guides or eyes resembling those that adorn the tips of peacock feathers. The eyes of M. aristata are usually outlined in violet or rarely yellow, and have broad black, hairy bases. The sturdy tepal claws are yellow and minutely speckled with black or violet. Individual blooms last only three days, but a succession of flowers is produced over a period of three to four weeks. The style has three conspicuous flat white branches. The erect, oblong seed capsules split open from the top downwards, liberating light brown, angular seeds in early summer.
Moraea aristata is a protected species and its conservation status is Critically Endangered as a result of urbanization.
Distribution and habitat
Endemic to clay slopes and flats of the northeastern Cape Peninsula, Moraea aristata occurs in remnant Peninsula Shale Renosterveld vegetation. The species is currently limited to a single subpopulation near the Liesbeek River in the suburb of Observatory. Despite its location within a protected area, it is on the verge of extinction there, as the limited number of individuals and low genetic diversity, poor seed production and disturbed site renders the subpopulation non-viable.
Derivation of name and historical background
In 1758 the Scottish horticulturist and botanist Philip Miller established the genus Morea in honour of Robert More of Shropshire. Carolus Linnaeus later altered its spelling to Moraea to associate the name with his father-in-law, J. Moraeus, a Swedish physician. The Latinised specific epithet aristata is descriptive of the long central lobe of the inner tepals that ends abruptly in a straight point or arista.
The plant was first described in 1766 when the Swiss botanist Daniel de la Roche named it Vieusseuxia aristata, and it was known under several other names applied to it by subsequent authors. Amongst several early illustrations of the plant is a beautifully executed one by the acclaimed Belgian painter and botanist, Pierre-Joseph Redouté, reproduced in the first volume of his magnificent work Les Liliacées, in 1803. M. aristata is known to have been in cultivation in Holland by the mid-eighteenth century but it is uncertain how the plant first reached Europe. Today it survives in cultivation mainly in specialist bulb collections, but it has escaped into the wild in western Australia where it may be potentially invasive.
Moraea aristata is a member of the group of species known as peacock moraeas that have showy rounded outer tepals with prominent nectar guides or eyes that attract beetle pollinators. This group includes well known species such as M. gigandra, M. tulbaghensis and M. villosa.
Comprising about 200 species, Moraea is widely distributed in sub-Saharan Africa, with outliers in the Mediterranean and the Middle East. Its area of highest diversity is in the winter rainfall zone of the Western Cape. Most moraeas are winter-growing, with smaller numbers of summer-growing and evergreen species.
I have grown M.aristata successfully at Kirstenbosch for many years and seeds have often been made available to members of the Botanical Society of South Africa, and occasionally corms have been offered at the annual Garden Fair of this society. During the early 1980s I made an attempt with several Kirstenbosch colleagues to bolster the only remaining M. aristata subpopulation by planting 200 additional corms close to the subpopulation, that had been propagated in the Kirstenbosch Bulb Nursery. Initially these additional plants performed well, but due to the fact that all material of this species in cultivation originates from this subpopulation with its limited genetic base, and the probability that the beetle pollinator no longer exists in sufficient numbers at this site, the number of individuals there has not increased.
Moraea aristata is pollinated by monkey beetles (Hopliini: Scarabaeidae) and these have often been observed on cultivated plants in the Bulb Nursery at Kirstenbosch. The beetles are attracted to the striking blue nectar guides located near the base of the three broad outer tepals. The beetles feed on the nectar and pollen, and in so doing, pollen is deposited onto their heads and backs. When the beetles leave the flowers they brush against the stigmas and pollination takes place when they visit other flowers. The seeds are locally dispersed from the ripe capsules by the shaking action of wind.
Uses and cultural aspects
The corms of Moraea fugax, formerly known as M. edulis, are known to have been eaten by the indigenous peoples of southern Africa, but those of M. aristata are not known to have been consumed. The latter species is used in ornamental horticulture by specialist bulb growers, mainly as a container plant, less frequently as a subject for rock garden pockets.
Growing Moraea aristata
Cultivating this species is easily achieved and it flowers prolifically in ideal conditions. The corms are planted in autumn at a depth of about 3 cm in a sandy or clayey medium into which finely sifted, well decomposed organic matter has been added. The plants need full sun or bright light and are most successfully cultivated under cover in deep plastic containers with a diameter of 30 cm, or in deep bulb beds. In temperate climates they can also be grown in dedicated rock garden pockets that are securely lined with wire mesh to exclude mole rats. In addition, the plants can be very successfully naturalised in buffalo grass (Stenotaphrum secundatum) that is not watered in summer, simply by scattering seeds over the grass in autumn and covering them with a 5 mm layer of equal parts river-sand and finely sifted compost. In cold climates of the Northern Hemisphere M. aristata is suited to cultivation in the cool greenhouse and requires bright light for as much of the day as possible. Regular heavy drenching of the growing medium is essential during the winter-growing and spring-flowering periods, but the corms must be kept completely dry throughout the summer dormant phase. The species is half-hardy and can withstand winter temperatures down to 0ºC or 32ºF. The plants flower from mid-August to September in the wild but in cultivation they often begin flowering in late July.
Moraea aristata is easily raised from fresh seeds (those harvested the previous season) sown in late autumn in deep seed trays, pots or directly into deep seed beds, in the same medium recommended for mature corms. Seeds should be sown at a depth of 3–4 mm and care should be taken not to sow too thickly to prevent overcrowding and reduce the chances of loss to damping-off fungi. Germination takes place within five to six weeks and seedlings should be allowed to grow undisturbed for two seasons before planting them into permanent positions at the beginning of their third season, during which some may flower for the first time, if well grown. In order to obtain pure seeds from cultivated plants it is necessary to cross-pollinate the flowers by hand as they are self-incompatible. In addition to seeds, M. aristata is readily propagated by cormlets that form at the tips of subterranean stolons. Cormlets are removed during the dormant period and potted-up individually, in the same way as mature corms. Propagative material (seeds and corms) is sometimes offered by specialist bulb nurseries in South Africa.
Moraea aristata is not especially susceptible to pests and diseases although the undersides of the leaves do frequently fall prey to attack by red spider mites as temperatures rise in late spring. Fungal rotting of the corms often occurs when they are not kept sufficiently dry during the summer dormant phase.
References and further reading
- Duncan, G.D. 1983. Moraea aristata. Veld & Flora 69(4): 143–144.
- Duncan, G.D. 1997. Moraeas of the Western Cape. Veld & Flora 83(2): 42–44.
- Duncan, G.D. 2002. Just holding on – spectacular geophytes in peril. Veld & Flora 88(4): 142–147.
- Du Plessis, N.M. & Duncan, G.D. 1989. Bulbous plants of southern Africa, a guide to their cultivation and propagation. Tafelberg, Cape Town.
- Goldblatt, P. 1986. The moraeas of southern Africa. Annals of Kirstenbosch Botanic Gardens 14. National Botanic Gardens, Cape Town.
- Jeppe, B.J. & Duncan, G.D. 1989. Spring and winter flowering bulbs of the Cape. Oxford University Press, Cape Town.
- Mucina, L. & Rutherford, M.C. 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.
- Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. & Manyama, P.A. 2009. Red List of South African plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
- Steiner, K.E. 1998. Beetle pollination of peacock moraeas (Iridaceae) in South Africa. Plant Systematics & Evolution 209: 47–65.
Kirstenbosch National Botanical Garden