Chasmanthe bicolor is a highly ornamental garden subject, which stands out from the other two species in this genus. It is one of three species in the genus, the others being Chasmanthe floribunda, which has a yellow variety C. floribunda var. duckittii and Chasmanthe aethiopica.

Description
This plant is a winter-growing, cormous geophyte up to 1.3 m high. The corm is 45mm in diameter, is slightly depressed and surrounded with several layers of dark brown, scaly leaf bases called tunics.

Although the flower is smaller that the other two species in the genus, it is more striking. The upper tepals of the flowers are orange-scarlet, whereas the bottom tepals are dark green with a yellow tube. The flowers are alternately arranged on both sides of the peduncle with as many as 28 blossoms. It blooms from midwinter to early spring (June–Sept.).

The leaves are sword-shaped and have a silky feel and look, with a prominent vein in the centre of each leaf. The leaves are arranged in a fan.

Conservation status
Chasmanthe bicolor is on the Red Data List. It is extremely rare to almost extinct in the wild.

Distribution and habitat
Chasmanthe bicolor is extremely rare. It is thought to be extinct in a large area of its natural habitat of Robertson, Caledon and Franschhoek. Chasmanthe bicolor is endemic to the Western Cape Province of South Africa. The geographic range is, however, not well known.

Derivation of name and historical aspects
The name Chasmanthe derives from the Greek words, chasme, meaning gaping mouth, and anthe, meaning flower. The word bicolor is Latin for two-coloured; referring to the colour of the flowers.

Ecology
The brightly coloured flowers of Chasmanthe bicolor ensure that the pollinators, sunbirds, are attracted to the plants. The flower has a wide base which contains nectar. The beak of the Orange-breasted sunbird and the Malachite sunbird is perfectly shaped to fit the curves of the flower. When the bird inserts its beak into the flower in search of nectar, the pollen on the stamen is deposited onto its beak.

Uses and cultural aspects
This plant can be used to bring much needed colour to those difficult semi-shaded areas in the garden. It can also be used as a container plant.

Growing Chasmanthe bicolor

Chasmanthe bicolor is very easily propagated. The pea-sized seeds are ready to be harvested once the capsule starts to split open. Sow in autumn (mid-April to May), 3–5 mm deep. This can be sown in deep seed trays, pots or seedbeds. Use a well-drained medium (1 part river sand or silica sand and 1 part fine compost). Fresh seed germinates within 3 to 4 weeks. Keep moist, water every 2 to 3 days with a fine sprayer. Large, mature clumps can be lifted and divided every 3 to 4 years. This must happen in the dormancy stage (during the summer and early autumn months).

References and further reading

• Goldblatt, P., Manning, J & Dunlop, G. 2004. Crocosmia and Chasmanthe. Royal Horticultural Society Plant Collectors Guide. Timber Press, Portland, Oregon
• Duncan, G. D.2001. Chasmanthe. Veld & Flora 87: 108–111.
• De Vos, M P. 1985. Revision of the South African genus Chasmanthe (Iridaceae). South African Journal of Botany 51: 252-261