If Pachypodium lamerei is the popular star of the genus, Pachypodium geayi is its elegant double — more slender, more understated, frequently confused with its cousin in garden centers but recognizable by its downy leaves and pale grey spines. Native to a narrow strip of southwestern Madagascar, this columnar species shares nearly all its cultivation requirements with Pachypodium lamerei, which makes the commercial confusion inconsequential for the grower. For the naturalist, the conservationist, and the collector who cares about taxonomic accuracy, however, correct identification matters — especially since its more restricted range makes it potentially more vulnerable to habitat destruction than Pachypodium lamerei. As with every species in the genus, the cardinal rule remains: less water is better.
Quick facts
| Parameter | Details |
|---|---|
| Botanical name | Pachypodium geayi Costantin & Bois (1907) |
| Family | Apocynaceae |
| Subfamily | Apocynoideae |
| Common names | Madagascar palm (shared with Pachypodium lamerei); Geay’s pachypodium (en.); palmier de Madagascar, Pachypodium de Geay (fr.); palma del Madagascar (it.) |
| Origin | Southwestern Madagascar (Toliara Province, from Morombe to Cap Sainte-Marie) |
| Habitat | Xerophytic spiny thicket on calcareous and sandy substrates, from sea level to about 1,000 ft (300 m) |
| Height | 10–26 ft (3–8 m) in the wild; 3–8 ft (1–2.5 m) indoors; up to 20–26 ft (6–8 m) in the ground in frost-free climates |
| Habit | Arborescent, columnar, unbranched, more slender and narrower than Pachypodium lamerei |
| Growth rate | 4–10 in (10–25 cm)/year in good conditions; 1.5–3 in (4–7 cm)/year indoors with moderate light |
| Hardiness | USDA 10a–11 (marginal in 10a with winter protection; reliable from 10b). Absolute minimum 50 °F (10 °C) in dry substrate; frost is fatal |
| Flowers | White with a yellow throat, fragrant, in terminal cymes. Very rare indoors. |
| Toxicity | Clear irritant sap. Sharp spines. Keep away from children and pets. |
| CITES | Appendix II |
| IUCN | Near Threatened (NT) |
| Difficulty | 2/5 — easy, provided you do not overwater |
Taxonomy
Pachypodium geayi was described in 1907 by the French botanists Julien Noël Costantin and Désiré Bois from specimens collected in southwestern Madagascar. The specific epithet honors François Geay, a French naturalist and collector who assembled numerous botanical and zoological specimens in Madagascar at the turn of the twentieth century.
The species belongs to section Pachypodium (formerly section Cactipodium), which groups the large columnar Malagasy species: Pachypodium lamerei, Pachypodium geayi, Pachypodium rutenbergianum, and Pachypodium mikea. All four share the arborescent, spine-covered trunk topped by a terminal leaf tuft, but they differ in leaf pubescence, spine color, floral morphology, and geographic distribution.
The relationship between Pachypodium geayi and Pachypodium lamerei is the subject of recurring debate. The two species are morphologically very close and their ranges partially overlap in southwestern Madagascar, where populations with intermediate characters have been reported (notably in the Itampolo area). Some authors have proposed treating Pachypodium geayi as a subspecies or variety of Pachypodium lamerei. However, molecular analyses published to date support their maintenance as distinct species, and this is the position adopted by POWO. The morphological separation criteria — leaf pubescence and spine color — are consistent and reliable across typical populations.
No infraspecific varieties or subspecies are currently recognized for Pachypodium geayi.
Morphology
Trunk: cylindrical, columnar, unbranched (monocaulous) unless injured or pruned, generally more slender and narrower than that of Pachypodium lamerei. The bark is smooth, silvery grey to greenish-grey, typically slightly paler than in Pachypodium lamerei. Basal diameter reaches 8–14 in (20–35 cm) on mature wild specimens — on average thinner than Pachypodium lamerei at comparable height. The trunk is succulent and serves as the primary water reservoir; it may wrinkle during drought, which is a normal signal.
Spines: arranged in triads at each leaf scar, as in Pachypodium lamerei. They are distinguished clearly by their color: pale grey to whitish-grey, sometimes almost silvery, whereas they are dark brown to reddish-brown in Pachypodium lamerei. This is the second most reliable diagnostic character between the two species. Length 0.4–0.8 in (1–2 cm), rigid and sharp, with a slightly hooked tip.
Leaves: spirally arranged at the trunk apex, forming a terminal tuft. Blade lanceolate, narrower than in Pachypodium lamerei — 0.8–1.6 in (2–4 cm) wide versus 1.2–2 in (3–5 cm) — and 6–12 in (15–30 cm) long, grey-green (rather than glossy dark green). The primary diagnostic character is the pubescence of the lower surface: a fine, short down, visible to the naked eye and distinctly perceptible by touch, covers the abaxial surface of the blade. In Pachypodium lamerei, the lower surface is completely glabrous. The midrib is prominent, greyish-green. Petiole short, 0.2–0.4 in (5–10 mm). Leaves are deciduous.
Flowers: large, 2.8–4 in (7–10 cm) in diameter, white with a yellow throat, fragrant, in terminal cymes. Morphologically near-identical to those of Pachypodium lamerei. Distinguishing the two species from flowers alone is extremely difficult without reference material. Pollinated by moths in Madagascar.
Fruit: a pair of divergent follicles, 4–6 in (10–15 cm) long, splitting at maturity to release winged seeds with a silky coma. Indistinguishable from those of Pachypodium lamerei.
Sap: clear, watery, slightly viscous, irritant. Properties identical to those of Pachypodium lamerei.
Similar species: comparison table
| Character | Pachypodium geayi | Pachypodium lamerei | Pachypodium rutenbergianum | Pachypodium mikea |
|---|---|---|---|---|
| Leaves (underside) | Pubescent (downy) | Glabrous (smooth) | Glabrous | Glabrous |
| Leaf color | Grey-green, narrow, 0.8–1.6 in (2–4 cm) wide | Glossy dark green, broader, 1.2–2 in (3–5 cm) wide | Medium green, broad | Grey-green, narrow |
| Spines | Pale grey to whitish | Dark brown to reddish-brown | Dark brown, shorter | Grey, fine |
| Habit | Unbranched, 10–26 ft (3–8 m), slender | Unbranched, 10–20 ft (3–6 m), stockier | Branched, 26–65 ft (8–20 m) | Unbranched, 6–13 ft (2–4 m) |
| Trunk diameter | 8–14 in (20–35 cm) at maturity in habitat | 12–16 in (30–40 cm) at maturity in habitat | 12–24 in (30–60 cm) | 6–10 in (15–25 cm) |
| Flowers | White, yellow throat | White, yellow throat (near-identical) | White, yellow throat, larger | White, yellow throat |
| Distribution | Southwestern Madagascar (narrow range) | Southern and southwestern (broader) | Western and northwestern | Southwestern coast (Mikea forest) |
| IUCN status | Near Threatened (NT) | Least Concern (LC) | Least Concern (LC) | Endangered (EN) |
| Hardiness | 50 °F (10 °C) min. Marginal 10a, reliable 10b. | 41–45 °F (5–7 °C) min. | 41–45 °F (5–7 °C) min. | 46–50 °F (8–10 °C) min. |
| Availability in cultivation | Common (specialist trade) | Very common | Uncommon | Rare |
How to tell Pachypodium geayi from Pachypodium lamerei in 10 seconds: turn a leaf over. If the underside is smooth to the touch, it is Pachypodium lamerei. If it is downy, it is Pachypodium geayi. If you do not have access to leaves (defoliated plant in winter), look at the spines: pale grey = Pachypodium geayi, dark brown = Pachypodium lamerei. This dual criterion is reliable across typical populations; intermediate populations from the contact zone (Itampolo) may be ambiguous.
Distribution and habitat
Pachypodium geayi is endemic to southwestern Madagascar, in Toliara Province. Its range is more restricted than that of Pachypodium lamerei: it extends along the southwestern coast, roughly from Morombe in the north to Cap Sainte-Marie at the extreme southern tip of the island, concentrated on the coastal strip and the calcareous plateaus of the Mahafaly and Androy regions.
The habitat is the Malagasy xerophytic spiny thicket, on calcareous, sandy, or sandy-calcareous substrates. Pachypodium geayi tends to occupy sites closer to the coast and at lower elevations than Pachypodium lamerei, generally from sea level to about 1,000 ft (300 m). It grows alongside Alluaudia procera, Alluaudia ascendens, Didierea madagascariensis, arborescent Euphorbia, and other Pachypodium species.
The climate is semi-arid to arid: 8–20 in (200–500 mm) of annual rainfall, concentrated from December to March. The dry season is long (7–9 months) and virtually rainless. Daytime temperatures frequently exceed 95 °F (35 °C) in summer; winter lows rarely drop below 54–59 °F (12–15 °C). Frost is unknown. This extreme seasonality explains the strictly deciduous behavior of the species: Pachypodium geayi sheds all its leaves during the dry season and only produces new ones when the rains return.
The range of Pachypodium geayi overlaps with that of Pachypodium lamerei in its southern and southwestern portions. In contact zones, individuals with intermediate characters (reduced leaf pubescence, variable spine color) have been reported, fueling the taxonomic debate about the degree of differentiation between the two species.
Conservation
Pachypodium geayi is listed under CITES Appendix II (trade regulated, export permits required). The IUCN classifies it as Near Threatened (NT), one step above Pachypodium lamerei (Least Concern). This more concerning classification reflects a more restricted range and sustained anthropogenic pressure.
The threats are the same as for the Malagasy spiny thicket as a whole: slash-and-burn agriculture (tavy and hatsake), charcoal production, collection of wild specimens for the horticultural trade, and expansion of goat grazing. Habitat loss is ongoing and accelerating: the spiny thicket of southwestern Madagascar has lost approximately 30% of its area over the past 30 years.
In cultivation, Pachypodium geayi is abundantly propagated from seed in nurseries. The vast majority of specimens available in the European and North American trade are nursery-grown. Purchasing documented nursery-propagated plants remains best practice.
Cultivation
| Parameter | Recommendation |
|---|---|
| Exposure | Full sun essential. Minimum 4–6 hours of direct sun/day. |
| Watering (summer) | Generous but infrequent: every 7–14 days. Let the top half of the substrate dry out. |
| Watering (winter) | Near zero. One light moistening/month at most. No watering if the plant is leafless. |
| Substrate | Mineral and fast-draining: 60–80% inorganic (pumice, perlite, coarse sand, lava rock). |
| Pot | Unglazed terracotta ideal. Drainage holes mandatory. Diameter = trunk base + 1–2 in (2–5 cm). |
| Repotting | Every 2–3 years in spring. Dry substrate; no watering for 7–10 days after. |
| Fertilizing | Low-nitrogen liquid fertilizer, half dose, once/month April through September. |
| Growing temperature | 65–95 °F (18–35 °C). Optimum 80–90 °F (27–32 °C). |
| Winter temperature | 50–65 °F (10–18 °C) ideal. Absolute minimum 50 °F (10 °C) in bone-dry substrate. Less cold-tolerant than Pachypodium lamerei. Frost is fatal. |
| USDA hardiness | 10a–11 (marginal in 10a with winter protection; reliable from 10b) |
In practice: the same care as Pachypodium lamerei
Let us be direct: if you can grow a Pachypodium lamerei, you can grow a Pachypodium geayi. The requirements are virtually identical. Substrate, watering, temperature, light, repotting, fertilizing — everything is interchangeable between the two species. The same mistakes kill both plants: too much water, too little light, watering during dormancy.
The cultural differences, to the extent they exist, are subtle and debated:
More slender habit: Pachypodium geayi tends to develop a slightly thinner and taller trunk than Pachypodium lamerei at comparable age. Indoors, this means it reaches the ceiling a little sooner but takes up less lateral space — an advantage in narrow rooms.
Cold sensitivity: Pachypodium geayi is noticeably less cold-tolerant than Pachypodium lamerei. It reacts more abruptly to cold snaps (faster leaf drop, slower recovery) and suffers tissue damage at temperatures that Pachypodium lamerei can tolerate in dry substrate. The practical minimum is 50 °F (10 °C) — higher than the 41–45 °F (5–7 °C) tolerated by Pachypodium lamerei. This places Pachypodium geayi as marginal in USDA zone 10a (outdoor cultivation possible only with winter protection) and reliable only from zone 10b onward.
Flowering: just as rare indoors as in Pachypodium lamerei. The same conditions are required: a mature specimen, intense sunlight, and a pronounced winter dormancy.
Growing Pachypodium geayi in temperate climates
The strategy is strictly identical to that of Pachypodium lamerei: indoor plant with summer placement outdoors and indoor overwintering. Permanent outdoor planting is only feasible in USDA zone 10b and warmer; in zone 10a, it is marginal and requires winter protection (unheated greenhouse, rain shelter, fleece during cold snaps). At temperate latitudes — and even along the Mediterranean coast (USDA 9b) — Pachypodium geayi is strictly a container plant that must be brought indoors for winter.
Summer outdoors (late May–late September): acclimate gradually over a week (dappled shade, then full sun). Protect from prolonged rain. This is the single most effective thing you can do for a thick, well-spined, healthy plant.
Winter indoors (October–April): brightest window available (south-facing ideal). Near-zero watering. If the plant drops all its leaves, do nothing — it is normal dormancy. Squeeze the trunk: firm = all is well.
Propagation
From seed
The standard method, as for all columnar species in the genus. Fresh seeds of Pachypodium geayi germinate in 3–7 days at 77–86 °F (25–30 °C), with germination rates of 80–90%. The protocol is identical to that of Pachypodium lamerei: soak for 24 hours in warm water, sow on the surface of a sterilized, free-draining mix (50% fine perlite, 30% sieved cactus mix, 20% coarse sand), cover with a clear lid, and maintain consistent warmth. Seedlings grow rapidly — 3–10 in (8–25 cm) in the first year under optimal conditions — and tolerate beginner mistakes. See our detailed guide: Growing Pachypodium from seed: a germination guide by species.
From offsets
Uncommon. Pachypodium geayi rarely produces basal offsets, and less frequently than Pachypodium lamerei. If an offset appears, remove it with a sterile blade, dry for 5–8 days, and pot into dry cactus mix. Do not water for 3–4 weeks.
From tip cuttings
Possible after pruning or accidental damage. Let the cut surface dry for at least a week, then place on dry mineral substrate. Rooting is slow and uncertain, but the success rate is comparable to that of Pachypodium lamerei — the best in the genus for this technique. The mother plant will branch below the cut point.
Grafting
Pachypodium geayi is not a species that is typically grafted (its growth rate is fast enough on its own roots). It can, however, serve as rootstock for slower species, in the same way as Pachypodium lamerei, though the latter is preferred due to its greater availability and superior root vigor.
Pests and diseases
The pest and disease profile of Pachypodium geayi is identical to that of Pachypodium lamerei. The same pests, the same pathogens, the same treatment protocols apply.
Trunk rot and root rot: the number one threat, caused by oomycete pathogens (Phytophthora, Pythium) in waterlogged substrate. The trunk becomes soft and spongy. Prevention: mineral-dominant, fast-draining substrate; drainage holes mandatory; no watering during dormancy. Treatment: surgical excision, drying for 5–7 days, repotting in dry mineral substrate.
Mealybugs: white cottony clusters at leaf bases and in spine crevices. The pale grey spines of Pachypodium geayi paradoxically make mealybugs slightly easier to spot than on the dark brown spines of Pachypodium lamerei, where the white clusters stand out less sharply. Treatment: cotton swab dipped in 70% rubbing alcohol; neem oil or insecticidal soap for heavy infestations.
Spider mites: common in heated indoor air during winter. Leaves develop a stippled, bronzed appearance; fine webbing may appear. Treatment: rinse with a strong water spray, apply neem oil, increase ambient humidity.
Root mealybugs: invisible above ground; detected when repotting (white cottony masses on roots). Treatment: rinse roots, soak in systemic insecticide solution, repot in fresh substrate.
Etiolation: the trunk becomes abnormally thin at the top due to insufficient light. More deceptive in Pachypodium geayi than in Pachypodium lamerei, because the naturally slender habit can mask the thinning — the grower may not realize the plant is etiolating until it is too late. Monitor the trunk diameter-to-height ratio: if the trunk is continuously tapering toward the top (instead of maintaining a roughly constant diameter), light is insufficient.
For detailed treatment protocols, see our guide: Pachypodium pests and diseases: diagnosis and treatment.
Landscape and design use
Container plant on a patio or balcony: the slender silhouette and silvery-grey tones of Pachypodium geayi (grey spines, grey-green leaves) blend with particular elegance into mineral compositions and contemporary gravel gardens. The contrast with a Pachypodium lamerei (brown spines, glossy dark green leaves) is subtle but real — the two species placed side by side create an interesting visual dialogue.
Indoor specimen: the narrower habit compared to Pachypodium lamerei makes it a slightly better choice for tight spaces. The sparser canopy casts less shade, allowing it to be placed in front of a window without darkening the room.
In-ground outdoors: permanent outdoor planting is reliable only in USDA zone 10b and warmer (southern Florida, Canary Islands, parts of southern Italy and southern Portugal). In zone 10a, it is marginal and requires winter protection — an unheated rain shelter, fleece during cold snaps, and a very well-drained mineral substrate. In zone 9b and below, Pachypodium geayi is strictly a container plant. The slender habit makes it well suited to greenhouses where lateral space is limited.
In combination: a natural companion for Alluaudia, Didierea, arborescent Euphorbia, and other Malagasy succulents in “spiny thicket” themed collections. In ornamental compositions, it pairs well with glaucous agaves (Agave franzosinii, Agave americana subsp. protamericana), Yucca rostrata, and silver-leaved ornamental grasses.
Frequently asked questions
How do I tell Pachypodium geayi from Pachypodium lamerei?
Turn a leaf over. Smooth underside = Pachypodium lamerei. Downy underside = Pachypodium geayi. If the plant is leafless, check the spines: dark brown = Pachypodium lamerei, pale grey = Pachypodium geayi. See our comparison guide: Pachypodium lamerei vs. Pachypodium geayi: how to tell them apart.
Is the Pachypodium geayi sold at my garden center really a Pachypodium geayi?
Not always. The vast majority of plants sold as “Madagascar palm” in retail garden centers are Pachypodium lamerei. Pachypodium geayi is considerably less common in the mass-market pipeline. Always check leaf pubescence and spine color before buying if identification matters to you. At specialist succulent nurseries, labeling is generally reliable.
Is the care different from Pachypodium lamerei?
Almost. Substrate, watering, light, and dormancy management are identical. The one meaningful difference is cold tolerance: Pachypodium geayi is less hardy, with a practical minimum of 50 °F (10 °C) versus 41–45 °F (5–7 °C) for Pachypodium lamerei. This makes it marginal outdoors in USDA zone 10a and reliable only from 10b, whereas Pachypodium lamerei can be grown outdoors from zone 9b with protection. In practice, bring Pachypodium geayi indoors earlier in autumn and keep it warmer during winter.
My Pachypodium geayi is losing its leaves in winter. Is this normal?
Yes. It is genetically programmed winter dormancy, identical to that of Pachypodium lamerei. Squeeze the trunk: if it is firm, the plant is fine. Stop watering, keep in bright light, wait for spring. For a comprehensive diagnosis of all leaf-drop causes, see: My Pachypodium is losing its leaves: causes, decision tree, and solutions.
Is Pachypodium geayi rarer than Pachypodium lamerei?
In cultivation, yes — it is significantly less common in the mass-market trade, though it remains readily available from specialist succulent nurseries. In the wild, it is classified as Near Threatened (NT) by the IUCN versus Least Concern (LC) for Pachypodium lamerei, owing to a more restricted range and sustained anthropogenic pressure on the spiny thicket of southwestern Madagascar.
Can Pachypodium geayi and Pachypodium lamerei hybridize?
Yes. The two species belong to the same section and hybridize freely through cross-pollination when they flower simultaneously. Natural hybrids are in fact suspected in contact zones in Madagascar. In cultivation, this means that seeds harvested from a Pachypodium geayi grown near a flowering Pachypodium lamerei may produce hybrids. This is not a problem for the hobbyist grower (hybrids are vigorous and perfectly cultivable), but it is important for anyone aiming to maintain pure lines for conservation or taxonomic purposes.
Bibliography
Costantin, J. & Bois, D. (1907). “Sur deux Pachypodium nouveaux de Madagascar.” Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences, 145: 268–269. [Original description of Pachypodium geayi]
Rapanarivo, S.H.J.V., Lavranos, J.J., Leeuwenberg, A.J.M. & Röösli, W. (1999). Pachypodium (Apocynaceae): taxonomy, habitats and cultivation. A.A. Balkema, Rotterdam. 107 pp.
Rowley, G.D. (1999). “Pachypodium and Adenium.” Cactus File Handbook, 5. Cirio Publishing, Southampton.
Lüthy, J.M. (2004). “Pachypodium — Notes on the taxonomy.” Cactus and Succulent Journal, 76(3): 126–131.
Rauh, W. (1995). Succulent and xerophytic plants of Madagascar, vol. 1. Strawberry Press, Mill Valley. 343 pp.
Callmander, M.W., Phillipson, P.B. & Lowry, P.P. II (2012). “Novelties from the spiny thicket: two new species of Pachypodium (Apocynaceae) from southern Madagascar.” Adansonia, sér. 3, 34(2): 279–285.
CITES (2024). Appendices I, II and III. Convention on International Trade in Endangered Species of Wild Fauna and Flora. https://cites.org/eng/app/appendices.php
POWO (2024). Pachypodium geayi Costantin & Bois. Plants of the World Online, Royal Botanic Gardens, Kew. https://powo.science.kew.org
IUCN (2024). Pachypodium geayi. The IUCN Red List of Threatened Species. https://www.iucnredlist.org