Chasmanthe is a genus of flowering plants endemic to the Cape Province in South Africa. The genus has three species – aethiopica, bicolor, and floribunda, the last of which comes in two varieties.
It needs no water from mid-spring through fall, but it can tolerate summer water if the soil is well-drained. Flowering stems should be cut back after the flowers fade (and before seeds form). When the leaves turn brown, they should be cut to the ground before new growth appears.
Plants can withstand light frosts, or you can dig and store the corms. Replant in early spring when heavy frost danger is past.
Chasmanthe will eventually form a raised mass of corms up to a three feet across. They will continue to bloom for years without being divided, but dividing clumps every three to four years will lead to heavier flowering. Lift when dormant and cut apart sections of corms or pry out individual ones. Small offsets should be discarded and the flattened, as should the dead corms that are stacked under each mature one. Replant right away.
While Chasmanthe will grow in infertile soil, an addition of compost will give the plants a boost and will improve drainage in heavier soils. Plant two to three inches deep and six to ten inches apart. Corms may not flower in the first year after transplanting.
Chasmanthe grow from quarter-inch orange seeds, collected when pods start to split open in late spring or early summer and planted in autumn. Plants grown from seed usually bloom in their third year.
Seed is sown in autumn in trays deep enough to give sufficient room for the growth of the developing roots. A 5″ deep tray is recommended. The medium must be well-drained and should be kept moist but not wet. The trays must be kept in a semi-shaded position for the first season. The young corms can be planted out into the garden at the beginning of their second season.
Germination of seeds in the greenhouse was very rapid and most had good germination rates.
Name Derivation: named for the way the petal tips spread widely, from the Greek chasmamai (yawning or gaping) and anthos (flower).
Chasmanthe is in the family Iridaceae.