Ceropegia
Ceropegia is a large and remarkably varied genus in the dogbane family (Apocynaceae, subfamily Asclepiadoideae), grown by succulent enthusiasts for its bizarre, intricately shaped lantern flowers — tubular blooms that work as tiny pitfall traps for pollinating flies. The genus spans delicate string-of-hearts trailers, wiry twining stems, and fat tuberous caudiciforms, and in recent taxonomic revisions it has absorbed the former genus Brachystelma, making it broader and more diverse than ever.
Description
Members of Ceropegia share the family's latex and paired seed pods, but their growth habits are astonishingly diverse. Many are slender twiners or trailers with thin stems and small, often heart-shaped or fleshy leaves; others are near-leafless succulents with thick, mottled, cactus-like stems; and a large group (including most of the plants once called Brachystelma) form squat underground tubers or caudexes that store water and push up seasonal shoots.
Whatever the body, the flowers are the genus's signature. Each bloom is a fused tube, often swollen at the base and flaring into five lobes at the mouth. The lobes are frequently joined at their tips to form a little cage or "lantern", and the whole structure is commonly striped, spotted, or fringed with hairs. These features are not decoration but a trap: small flies are lured inside, held briefly by downward-pointing hairs while they pick up pollen, then released unharmed when the hairs wither. The plants are not carnivorous — the trap serves pollination, not digestion.
Distribution
Ceropegia is an Old World genus, distributed across sub-Saharan and southern Africa, Madagascar, the Arabian Peninsula, the Indian subcontinent, and into Southeast Asia and northern Australia. Africa and India are the main centres of diversity. Species occupy a wide range of habitats — from seasonally dry grassland and scrub, where tuberous kinds survive drought underground, to rocky slopes and the light shade of woodland, where the trailing and twining species scramble through other vegetation.
Notable species
- Ceropegia woodii — the beloved string of hearts (also called rosary vine), a cascading trailer with silver-marbled heart-shaped leaves and small aerial tubers along the stems; the most widely grown species in the genus.
- Ceropegia sandersonii — the parachute plant, named for its large green flowers whose flared, umbrella-like lobes are held together at the tips.
- Ceropegia stapeliiformis — a creeping species with thick, mottled, snake-like stems resembling a Stapelia.
- Ceropegia haygarthii — a twiner bearing especially ornate flowers topped with a hairy, antenna-like appendage.
- Ceropegia ampliata — noted for plump white-and-green lantern flowers on nearly leafless stems.
- Ceropegia linearis — a trailing species closely allied to C. woodii, with narrow leaves.
Cultivation
As a group, Ceropegia are forgiving succulents that reward light-handed care. Grow them in a free-draining mix — a gritty succulent blend suits the tuberous and thick-stemmed kinds, while trailers like Ceropegia woodii tolerate a slightly richer mix so long as it drains freely. Bright, indirect light keeps leaf markings crisp and growth compact; too little light stretches the stems and fades the patterning, while harsh midday sun can scorch thinner-leaved species.
Water moderately during active growth and let the medium dry between waterings — the tubers and fleshy stems are prone to rot if kept wet. Reduce watering sharply in winter, especially for the deciduous, tuber-forming species, which naturally rest during the dry season and may drop their top growth entirely. Most are frost-tender and are best kept above freezing; see Watering and Repotting for general technique.
Propagation
The trailing and twining species are among the easiest of all succulents to propagate from stem cuttings, which root quickly in a gritty mix. Many, such as Ceropegia woodii, also form small aerial tubers along the stems that can be pressed onto the soil surface to root into new plants. Tuberous species are grown from seed or by careful division of the tuber. The paired seed pods release flat seeds tipped with a silky parachute of hairs, dispersed by wind.
Hobby and cultivar notes
Ceropegia woodii dominates the genus in cultivation and comes in several selected forms, including variegated 'Variegata' (pink-and-cream leaves) and the compact, tightly-leaved 'Silver Glory'. As with most variegated succulents, variegated string-of-hearts grows more slowly and needs bright light to hold its colour. Beyond C. woodii, collectors prize the flower-focused species — parachute plants and their relatives — grown as much for the spectacle of the blooms as for the foliage. The absorption of the former Brachystelma has brought a wave of stout, caudex-forming species into the genus, of growing interest to caudiciform collectors.
See also
- Stapelia · Huernia — related carrion-flower genera in the same subfamily
- Soil and potting mix · Watering · Repotting
- Propagation — cuttings · Propagation — offsets · Propagation — seed
- Pests and diseases