The Apocynaceae — the dogbane family — is one of the largest flowering plant families on Earth, with over 5,000 species spread across some 400 genera. Most people encounter it through oleanders, periwinkles, or the milkweeds that feed Monarch butterflies. But hidden within this vast family is one of the richest concentrations of succulent plants in the entire plant kingdom: caudiciform trees with swollen trunks that store water through months of drought, stem succulents that photosynthesize through their bare green stems, wax-leaved epiphytes that cling to tropical canopies, and bizarre carrion flowers that smell of rotting meat to attract pollinating flies.
This page is the gateway to all succulent Apocynaceae covered on succulentes.net. The family is divided into five subfamilies; the succulent genera are concentrated in two of them — Apocynoideae (which includes Pachypodium, Adenium, and Plumeria) and Asclepiadoideae (formerly treated as the separate family Asclepiadaceae, which includes the stapeliads, Ceropegia, Hoya, and the caudiciform climbers). Together, they represent one of the most morphologically diverse assemblages of succulents in the world — from 26-foot trees in Madagascar to 2-inch carrion-scented buttons in the Namib Desert.
The caudiciform giants: Pachypodium
Pachypodium (Greek: « thick foot ») is the flagship genus of succulent Apocynaceae and the one most familiar to collectors of caudiciform plants. The genus comprises 25 species, of which 20 are endemic to Madagascar and 5 to southern Africa. All are spiny, all store water in swollen trunks or subterranean caudices, and all are listed under CITES (four on Appendix I, the rest on Appendix II).
The morphological range is extraordinary. Section Leucopodium contains the columnar « Madagascar palms » — Pachypodium lamerei, Pachypodium geayi, Pachypodium rutenbergianum — which grow as spiny trees reaching 6 to 26 feet (2–8 m). Section Gymnopus holds the caudiciform darlings of the collector world: Pachypodium gracilius with its perfectly spherical silver caudex, Pachypodium brevicaule resembling a puddle of molten silver lava, Pachypodium rosulatum and its five subspecies. Section Porphyropodium contains the only red-flowered species: the critically endangered Pachypodium baronii and Pachypodium windsorii. The African species — Pachypodium succulentum, Pachypodium bispinosum, Pachypodium namaquanum (the legendary « Halfmens » of the Richtersveld), Pachypodium lealii, and Pachypodium saundersii — include the only frost-tolerant members of the genus.
The sap of Pachypodium is clear (never milky), irritant, and in some species toxic enough to serve as arrow poison. Despite superficial similarities, Pachypodium and Adenium are not closely related within the Apocynaceae — they belong to different phylogenetic lineages within the subfamily Apocynoideae.
For the complete species list, classification, cultivation guide, and conservation overview, see our dedicated hub Genus Pachypodium
The desert roses: Adenium
Adenium is the other great caudiciform genus of the family, and arguably the most commercially important succulent Apocynaceae worldwide thanks to the massive bonsai and hybridization industry centered in Thailand. The taxonomy is debated: some authorities recognize a single highly variable species (Adenium obesum) with multiple subspecies, while others accept five to six distinct species. In practice, growers and collectors use the following names:
| Species / subspecies | Common name | Range | Key feature |
|---|---|---|---|
| Adenium obesum | Desert rose | Sahel to East Africa, Arabian Peninsula | The most widely cultivated. Globose caudex, pink to red flowers. Tens of thousands of named hybrids and cultivars, especially from Thai breeding programs. |
| Adenium arabicum | — | Saudi Arabia, Yemen, Oman | The fattest caudex of the genus — squat, massive, with thick fleshy leaves. Popular with « fat plant » collectors. Often treated as a subspecies of Adenium obesum. |
| Adenium socotranum | — | Socotra (Yemen) | The giant of the genus: conical trunk up to 8 ft (2.5 m) in diameter, resembling a miniature baobab. Endemic to a single island. Extremely slow-growing. |
| Adenium multiflorum | Impala lily | South Africa, Mozambique, Zimbabwe | Slender trunk, exceptionally fragrant flowers with red-striped white petals. Widely grafted onto oleander rootstock for the European market. |
| Adenium boehmianum | — | Namibia, Angola, Botswana | Broad, non-glossy leaves. Sap used as arrow poison. Up to 5 ft (1.5 m). |
| Adenium swazicum | Summer-flowering impala lily | Eswatini, Mozambique | Dwarf habit (under 12 in / 30 cm), uniform pink to crimson flowers. Critically Endangered in habitat. Parent of many cold-tolerant hybrids (notably « Arizona » crosses by Dr. Mark Dimmitt). |
| Adenium oleifolium | — | South Africa, Botswana, Namibia | The smallest species: subterranean caudex, narrow olive-green leaves. Extremely slow-growing. Near Threatened. |
| Adenium somalense | — | Somalia, Kenya, Tanzania | The tallest species: up to 16 ft (5 m). Fast-growing. Includes var. crispum with wavy leaves and a swollen base. |
Unlike Pachypodium, Adenium exudes a milky white latex when cut — one of the most reliable ways to tell the two genera apart. The latex contains potent cardiac glycosides used as arrow poison across Africa. All parts are toxic to humans and animals.
Adenium cultivation follows the same broad principles as Pachypodium — full sun, excellent drainage, generous summer watering, dry winter rest — but with some important differences. Adenium is even more cold-sensitive than most Pachypodium (absolute minimum 50 °F / 10 °C for most species), has no spines, and responds spectacularly to grafting, which has made it one of the most hybridized ornamental plants in Southeast Asia.
The frangipani: Plumeria
Plumeria (frangipani) occupies a unique position among succulent Apocynaceae: it is not a caudiciform, not a stem succulent, and not a desert plant — yet its thick, fleshy branches store water efficiently enough to qualify as a pachycaul succulent, and it belongs squarely within the Apocynoideae alongside Pachypodium and Adenium. The genus comprises approximately 11 species native to tropical Central America, Mexico, and the Caribbean, with Plumeria rubra and Plumeria obtusa as the most widely cultivated.
Frangipani is grown throughout the tropics as an ornamental tree, prized above all for its intensely fragrant flowers — the iconic lei flower of Hawaii, the temple flower of Southeast Asia, the symbol of eternal life in Mesoamerican cultures. The flowers come in white, yellow, pink, red, and a seemingly infinite range of bicolored and gradient forms, thanks to extensive hybridization. Like Adenium, the genus produces milky latex and all parts are mildly toxic.
In temperate climates, Plumeria is grown as a container plant that spends summers outdoors and winters indoors in a cool, dry, brightly lit room — a management cycle almost identical to that of Pachypodium lamerei. It is deciduous, dropping all its leaves in autumn, and must not be watered while leafless. The minimum overwintering temperature is approximately 45–50 °F (7–10 °C). The genus is not listed under CITES.
The stapeliads: carrion flowers and their allies
The stapeliads are a large, informal grouping of stem-succulent genera within the subfamily Asclepiadoideae. They were formerly placed in the separate family Asclepiadaceae, but molecular phylogenetics has since merged the asclepiads into Apocynaceae. The stapeliads are among the most bizarre and visually striking of all succulents: leafless (or nearly so), with angular, fleshy green stems that photosynthesize directly, and flowers that range from stunningly beautiful to spectacularly repulsive — many produce odors mimicking decaying flesh to attract fly pollinators.
The principal genera of horticultural interest include:
Stapelia — The classic « carrion flower. » Star-shaped, often large (up to 16 in / 40 cm diameter in Stapelia gigantea), hairy, maroon-mottled, spectacularly malodorous. About 50 species, mostly from southern Africa. The most commonly cultivated genus of the group.
Huernia — Smaller, more compact stems than Stapelia, with bell-shaped or doughnut-shaped flowers in stunning geometric patterns. About 65 species. Easier to grow than most stapeliads — excellent beginner plants for the group.
Orbea (formerly part of Stapelia) — About 55 species. Flowers with a raised central disc (annulus). Orbea variegata is one of the most widely grown stapeliads.
Hoodia — Large, columnar, heavily spined stems. Made internationally famous (and controversial) in the early 2000s for alleged appetite-suppressant properties, claimed from traditional San use. About 14 species, mostly from the Namib Desert region.
Caralluma — About 120 species, widespread across Africa, the Mediterranean, the Middle East, and India. Small angular stems. Some species (Caralluma europaea) reach the southern coast of Spain — one of the few succulent Asclepiadoideae native to Europe.
Pseudolithos — Perhaps the most bizarre of all: stemless, roughly spherical, resembling a pebble or a small brain. Extremely difficult in cultivation. About 6 species from the Horn of Africa.
Edithcolea — The « Persian carpet flower. » A single species (Edithcolea grandis) with one of the most geometrically intricate flowers in the plant kingdom. Notoriously difficult to grow.
Other notable stapeliad genera include Duvalia, Piaranthus, Stapelianthus (endemic to Madagascar), Tavaresia, Larryleachia, and Echidnopsis.
All stapeliads require very well-drained mineral substrate, bright light (though many tolerate more shade than cacti), warm temperatures, and careful winter watering. Root rot is the primary killer. Most are easily propagated from stem cuttings.
The lantern flowers and rosary vines: Ceropegia
Ceropegia is a large genus of approximately 200 species, mostly from Africa, Madagascar, and southern Asia. The genus is extraordinarily diverse: some species are tuberous-rooted caudiciform climbers, others are stem succulents, and a few are epiphytes. What unites them is the extraordinary structure of their flowers — tubular, often swollen at the base, with the petal tips fused into a cage-like or lantern-like structure that temporarily traps pollinating flies.
The most widely cultivated species is Ceropegia woodii — the « chain of hearts » or « rosary vine » — a trailing plant with small, heart-shaped, succulent leaves and a tuberous caudex at the base. It is one of the most popular hanging houseplants worldwide. Other notable species include Ceropegia ampliata (parachute flower), Ceropegia sandersonii (fountain flower), and Ceropegia stapeliiformis (a stem succulent that mimics a stapeliad).
Note: following recent molecular work, the genus Brachystelma (about 100 species of tuberous-rooted caudiciform plants) has been sunk into Ceropegia, massively expanding the genus.
The wax plants: Hoya
Hoya comprises 200–300 species (taxonomy is still being revised) of mostly epiphytic or lithophytic climbers from tropical Asia, Australia, and the Pacific. While not caudiciform, many species have thick, succulent leaves and produce spectacular umbels of waxy, fragrant, often star-shaped flowers that exude nectar. Hoya carnosa (wax plant) and Hoya kerrii (sweetheart hoya, sold as a single heart-shaped leaf for Valentine’s Day) are among the most popular houseplants in the world.
Hoya is included here because it belongs to the Asclepiadoideae and shares the specialized pollination mechanism (pollinia) of the stapeliads and Ceropegia. In cultivation, hoyas require bright indirect light, well-draining epiphytic substrate (similar to orchid mix), and higher humidity than most other succulent Apocynaceae. They do not appreciate being moved once they have found a good position — a trait they share with Schlumbergera among the cactus epiphytes.
The caudiciform climbers: Fockea, Raphionacme, and allies
Several lesser-known genera of Asclepiadoideae produce large, subterranean or partially exposed caudices from which thin, twining stems emerge seasonally. These are prized by caudiciform collectors for their sculptural root-bases and ease of cultivation.
Fockea — About 6 species from southern Africa. Large, potato-shaped caudex (up to 24 in / 60 cm diameter) with thin, twining stems and small leaves. Fockea edulis is the most widely cultivated — the caudex is edible when cooked (hence the name), making it one of the very few caudiciform succulents with documented food use. Easy in cultivation, tolerates more water than most caudiciforms.
Raphionacme — About 35 species from tropical and southern Africa. Large tuberous caudex, thin climbing stems. Less commonly cultivated than Fockea but increasingly available from specialist nurseries. Raphionacme flanaganii is the species most often seen in collections.
Cynanchum — A vast genus (400+ species worldwide), but a handful of Malagasy species produce thick, fleshy, cactus-like stems and are cultivated as curiosities. Cynanchum marnierianum (formerly Folotsia grandiflora) from Madagascar is a striking succulent climber.
How to tell the major genera apart
| Feature | Pachypodium | Adenium | Plumeria | Stapeliads |
|---|---|---|---|---|
| Spines | Always present | Absent | Absent | Absent (teeth or tubercles, not true spines) |
| Sap | Clear, watery | Milky white latex | Milky white latex | Clear or slightly milky |
| Leaves | Present (deciduous) | Present (deciduous) | Present (deciduous) | Absent or vestigial |
| Growth form | Caudiciform tree or shrub | Caudiciform shrub | Pachycaul tree | Stem succulent (no trunk) |
| Flower color | White, yellow, or red | Pink, red, white (funnel-shaped) | White, yellow, pink, red (fragrant) | Brown, maroon, yellow (often malodorous) |
| Origin | Madagascar, southern Africa | Africa, Arabian Peninsula | Central America, Caribbean | Mostly Africa, some in Asia |
| CITES | All species (App. I or II) | Not listed | Not listed | Some Hoodia spp. (App. II) |
Shared cultivation principles
Despite their morphological diversity, the succulent Apocynaceae share a core set of cultivation requirements that reflect their common adaptation to seasonally dry tropical environments:
Full sun or very bright light. All the major genera — Pachypodium, Adenium, Plumeria, stapeliads — need intense light to maintain compact growth, strong spination (where applicable), and flowering. The partial exceptions are Hoya (bright indirect light) and some forest-floor stapeliads.
Excellent drainage. Root rot is the primary killer across the entire group. Mineral-dominant substrates (60–80% pumice, perlite, coarse sand, lava rock) are recommended for all caudiciform species. Stapeliads are particularly sensitive to stagnant moisture.
Seasonal watering. Generous watering during the summer growing season (allow the substrate to dry between waterings), sharp reduction in autumn, and near-total cessation in winter for deciduous species. The golden rule for Pachypodium and Adenium applies broadly: never water a leafless plant.
Warm temperatures. Most succulent Apocynaceae are tropical or subtropical — minimum 50–55 °F (10–12 °C) for the Malagasy and tropical African species. The notable exceptions are the South African caudiciforms (Pachypodium succulentum, Pachypodium bispinosum, Fockea edulis), which tolerate brief freezing.
Toxicity. The Apocynaceae is one of the most toxic plant families. Cardiac glycosides (Adenium, Nerium), irritant sap (Pachypodium, Plumeria), and various alkaloids are present across the group. Handle with gloves, keep away from children and pets, and wash hands after any contact with sap.
Frequently asked questions
Are Pachypodium and Adenium closely related?
Less than you might think. Both belong to the subfamily Apocynoideae within Apocynaceae, but molecular phylogenetics shows they are not sister genera — they evolved their caudiciform habit independently. The superficial resemblance (swollen trunk, deciduous leaves, showy flowers) is a case of convergent evolution driven by similar arid environments.
Are stapeliads really Apocynaceae? I thought they were Asclepiadaceae.
The family Asclepiadaceae (milkweed family) has been merged into Apocynaceae following molecular studies that showed the two groups are not separate evolutionary lineages. The former asclepiads now form the subfamily Asclepiadoideae within Apocynaceae. In practice, most growers still use the informal term « asclepiads » or « stapeliads » for convenience.
Can I grow Pachypodium and Adenium in the same conditions?
Mostly yes — both need full sun, excellent drainage, generous summer water, dry winter rest, and warm temperatures. The main differences: Adenium is slightly more cold-sensitive (minimum 50 °F / 10 °C vs. 45 °F / 7 °C for some Pachypodium), has no spines (easier to handle), and responds well to grafting and aggressive pruning — techniques rarely used with Pachypodium.
Is frangipani (Plumeria) a succulent?
It occupies a gray zone. Plumeria has thick, fleshy branches that store water, drops its leaves in drought, and survives months without irrigation — all hallmarks of succulence. But it lacks the extreme water-storage specializations of Pachypodium or Adenium. Botanists classify it as a pachycaul (thick-stemmed) rather than a true succulent. In cultivation, however, its management cycle is virtually identical to that of a tropical caudiciform succulent.
Read more
This hub page provides an overview of the succulent Apocynaceae. For in-depth coverage of each genus, see our dedicated guides:
Pachypodium:
- Pachypodium: the complete guide to Madagascar palms — All 25 species, classification, conservation, and cultivation.
- How to care for a Pachypodium lamerei (Madagascar palm) indoors
- Pachypodium pests and diseases: diagnosis and treatment
- Growing Pachypodium from seed
Adenium:
- Adenium: the complete guide to desert roses — Species, hybrids, grafting, and bonsai culture.
- How to care for an Adenium obesum (desert rose) indoors
- Adenium from seed: germination, first year care, and caudex development
Plumeria:
- Plumeria: the complete guide to frangipani — Species, fragrance profiles, and container culture in temperate climates.
Stapeliads and allies:
- Stapeliads: the complete guide to carrion flowers — Stapelia, Huernia, Orbea, Hoodia, and allies.
- Ceropegia: lantern flowers and rosary vines
- Hoya: the wax plants