Encephalartos altensteinii

Encephalartos altensteinii is a large, trunk-forming cycad of South Africa’s Eastern Cape, where it grows in coastal thicket and wooded valleys from the Bushmans River to the southern border of KwaZulu-Natal. Described in 1834 by Johann Georg Christian Lehmann, this species of the genus Encephalartos eventually forms one or several trunks about 4 m tall, occasionally 7 m, crowned with long, glossy green leaves whose leaflets carry a few teeth. It is one of the most widely grown cycads in the world, and one specimen is famous in Britain: the plant in the Palm House at Kew, brought from the Cape in 1775 and often described as the oldest pot plant in the world. The IUCN lists the species as Vulnerable. Its modest cold tolerance limits outdoor planting to mild, almost frost-free climates.

Key facts about Encephalartos altensteinii

  • Accepted name: Encephalartos altensteinii Lehm. (1834), accepted by The World List of Cycads (version 2026.08.15), GBIF and Species+
  • Former names and synonyms: Encephalartos marumii de Vriese (1838), Encephalartos vroomii Mast. and Zamia vernicosa Mast. (1868), Encephalartos regalis W.Bull (1889) and several nineteenth-century varieties named by Miquel and Regel, all synonyms according to The World List of Cycads
  • Family: Zamiaceae, order Cycadales
  • Common names: Eastern Cape cycad, Eastern Cape giant cycad (English); oos-kaapse broodboom (Afrikaans); umphanga, umguza, isundu (Xhosa), according to PlantZAfrica
  • Natural range: South Africa, Eastern Cape, from the Bushmans River (Alexandria district) to the southern border of KwaZulu-Natal, mostly near the coast
  • IUCN status: Vulnerable (VU, criterion A2acd), assessment by J. D. Bösenberg dated May 2020 and published in 2022
  • CITES and other protection: CITES Appendix I (whole genus, since 1977); Annex A in the European Union
  • Documented hardiness: foliage killed at about −4 °C (25 °F) according to a grower on the French Riviera; losses reported at −6 and −7 °C (21 and 19 °F) in Roussillon, southern France; defoliated plants survived −13 to −16 °C (9 to 4 °F) unprotected in North Carolina in the winter of 2013–2014 (see Cold hardiness)
  • Light and soil: full sun or light shade, free-draining soil; in the wild, coastal thicket, wooded riverbanks and rocky slopes
  • Habit and adult size: trunk single or branched at the base, up to about 4 m (rarely 7 m, then usually reclining) and 25 to 35 cm thick; leaves 1.5 to 3 m, rarely 4 m (Dyer, 1965)
  • In the UK, US and Australia: Kew (Palm House, since 1775) and several other British gardens; Montgomery Botanical Center, Fairchild, the Huntington, Lotusland, San Diego Botanic Garden and many other American gardens; thirteen plants in outdoor beds at the Royal Botanic Gardens Victoria, Melbourne
  • Toxicity: seeds and tissues to be treated as poisonous, as in other Encephalartos (see Toxicity and precautions)

How to recognise Encephalartos altensteinii

Look for tall, bare trunks, bright glossy green leaves and, above all, the base of the leaf stalk: the leaflets dwindle towards the base without turning into the series of spines seen in related species. In his revision of the cycads of southern Africa, R. Allen Dyer (1965) describes it as follows:

  • Trunk: single or branched at the base, up to about 4 m tall, rarely 7 m and then usually reclining, 25 to 35 cm in diameter, with a little wool at the apex
  • Leaves: 1.5 to 3 m, rarely 4 m long, almost straight in exposed sites and arching in shade, hairy when young, then smooth; the leaflets decrease towards the base of the leaf without becoming spines
  • Leaflets: middle leaflets up to about 15 cm long and 2 to 5 cm wide, fairly rigid in full sun, little tapered, ending in a sharp point, with one or two teeth (less often three to five) on one or both margins
  • Cones: two to five together, rarely one, yellowish green; male cones subcylindrical, up to about 50 cm long and 12 cm wide, with scales ending in an upturned beak; female cones more or less ovoid, 40 to 55 cm long and 20 to 28 cm wide, with wrinkled, warty scales
  • Seeds: scarlet, 3.5 to 4 cm long and 2 to 2.5 cm wide

The number and size of the teeth vary a great deal. Dyer notes that the type plate shows many regular teeth, like the plants on the west bank of the Bushmans River, whereas further east there are plants with almost entire leaflets. Lehmann’s original description (1834) already mentions a bare trunk of 4 to 5 feet, leaves of 4 to 5 feet and 30 to 40 pairs of glossy leaflets armed with two to five widely spaced teeth on each margin. PlantZAfrica adds that young leaves are light green, that leaves reach 2 to 3 m in shade but stay shorter in full sun, and that the plant produces a flush of leaves in spring, though not necessarily every year.

Encephalartos altensteinii
Encephalartos altensteinii grown under glass at the Palmengarten in Frankfurt, Germany.

Hybrids

According to Dyer (1965), Encephalartos altensteinii is the species most involved in natural hybridisation in the genus. In the valleys of the Bushmans, Great Fish and Buffalo rivers it grows alongside Encephalartos trispinosus and Encephalartos villosus, and not far from Encephalartos arenarius and Encephalartos latifrons; intermediate plants found there strongly suggest crossing. Dyer regarded hybridisation with Encephalartos villosus as “practically proved” where the two species meet. An article in the newsletter of The Cycad Society (Wrinkle, 1983) mentions hybrids with these four species and describes, near the Bushmans River, a very robust form with large, spiny leaflets, which it attributes to the influence of Encephalartos trispinosus.

In cultivation, crosses happen easily when several species cone at the same time: a plant raised from garden-collected seed is not necessarily pure.

Possible confusion

The commonest confusion is with Encephalartos natalensis, long included in a broad view of Encephalartos altensteinii. Dyer (1965) explains that the plants of the Natal Midlands formerly called Encephalartos altensteinii belong to Encephalartos natalensis, and gives a fairly constant character to separate them: in Encephalartos natalensis the leaflets are reduced to several spines on each side of the base of the leaf stalk, whereas in Encephalartos altensteinii they get smaller without becoming spines. Their habitats differ too: the first is confined to inland cliffs and ravines, the second is common in coastal vegetation.

PlantZAfrica also compares it with Encephalartos lebomboensis, a species of the Lebombo Mountains further north. Dyer points out that a hybrid between Encephalartos altensteinii and Encephalartos villosus would key out, in his key, to Encephalartos natalensis or Encephalartos lebomboensis: a plant of unknown origin may therefore be misnamed. Encephalartos longifolius, a close relative according to Dyer, has leaflets that are usually entire and often bluish; a plant of Encephalartos altensteinii grown in full sun can nevertheless cause confusion. Their ranges do not overlap in the wild.

Old garden labels deserve caution. In France, a plant photographed under this name at the Villa Thuret in Antibes was identified in 2014 by a member of the Fous de palmiers forum as Encephalartos trispinosus or a hybrid rather than the species itself.

Taxonomy

Encephalartos altensteinii is accepted by The World List of Cycads, GBIF and Species+. Lehmann published it on 15 March 1834 in the Allgemeine Gartenzeitung (volume 2, no. 11, p. 85), and again the same year in the sixth fascicle of his Novarum et minus cognitarum stirpium pugillus (p. 11, plates 4 and 5). The World List of Cycads treats these plates as a probable lectotype. In the same work Lehmann created the genus Encephalartos for the cycads of southern Africa, until then placed in Zamia.

The name has not changed since, but the concept of the species has narrowed. In the nineteenth century many plants grown in Europe received separate names, now synonyms according to The World List of Cycads: Encephalartos marumii de Vriese (1838), Encephalartos vroomii Mast. and Zamia vernicosa Mast. (1868), Encephalartos longifolius var. hookeri Miq. (1868), Encephalartos regalis W.Bull (1889), and Miquel’s varieties angustifolius and semidentatus (1842) and Regel’s distans, grandis, macrophyllus, parvifolius and spinosior (1874–1875). In the twentieth century the inland plants of Natal were separated as Encephalartos natalensis (see Possible confusion). Finally, the first Encephalartos woodii, found in 1895, was first mentioned by John Medley Wood as “Encephalartos altensteinii var. bispinosa” in his annual report for 1906–1907, before being described as a species in 1908 (Dyer, 1965).

Etymology and history

The epithet honours Baron Karl vom Stein zum Altenstein (1770–1840), a Prussian statesman at the court of King Frederick William III and a patron of science (Haynes, 2022, via The World List of Cycads; PlantZAfrica). The genus name, coined by Lehmann, comes from the Greek enkephalos (what is inside the head, the pith) and artos (bread), because local people made a kind of bread from the pith of the trunks; Lehmann adds, after Thunberg, that European settlers called these plants “broodboom”, bread tree.

According to Lehmann (1834), Christian Ecklon and Karl Zeyher found three new species of Encephalartos in 1832, this one among them, in the land of the Thembu, more than 800 miles from Cape Town, among thickets of succulent shrubs, Rhamnaceae and Celastraceae; he places Encephalartos altensteinii on the humus-rich soils of the hills. Dyer (1965) thought that the plant shown on the type plate probably came from the west bank of the Bushmans River, the first area reached by botanists travelling from the west.

The species was in cultivation in Europe long before it had a name. According to Guinness World Records, the specimen in the Palm House at the Royal Botanic Gardens, Kew, was brought from South Africa and planted in 1775, which makes it the oldest pot plant in the world. A 2025 article on cycad collections describes it as the living type specimen of the species, growing at Kew since 1775 (Deloso et al., 2025). According to a Live Science article (2011) based on information from Kew, it was collected in the Eastern Cape by Francis Masson, Kew’s first plant hunter, was one of the first plants installed in the Palm House when it opened in 1848, is said to have produced a single cone, in 1819, and was repotted in 2009 into a special container, the plant then weighing more than a tonne.

Common names

PlantZAfrica (SANBI) gives the English names Eastern Cape cycad and Eastern Cape giant cycad, the Afrikaans oos-kaapse broodboom and the Xhosa names umphanga, umguza and isundu; Species+ uses the two English names. The Gymnosperm Database cites, after Palmer and Pitman (1972), “broodboom” and the Zulu name uJobane. In South Africa “broodboom” (bread tree) is used for Encephalartos in general, not just this species, and the Xhosa names umguza and umphanga are also given by PlantZAfrica for Encephalartos natalensis. No English name honouring Altenstein is attested.

In the wild

Encephalartos altensteinii is endemic to South Africa. According to Dyer (1965), it reaches its western limit in the coastal thicket on the west bank of the Bushmans River, in the Alexandria district, goes furthest inland in the King William’s Town district and extends east to the southern border of Natal. PlantZAfrica describes it in coastal bush from the Bushmans River to the southern border of KwaZulu-Natal, and inland at Komga, Kei Road and King William’s Town, on rocky hills and exposed escarpments. The World List of Cycads gives only the Eastern Cape. An article by The Cycad Society (Wrinkle, 1983) describes plants along wooded riverbanks north of East London, hidden among tall trees.

Summers are warm and winters cool, with rare frosts, and annual rainfall reaches 800 to 1,000 mm (PlantZAfrica). Like all species in the genus, it is pollinated by insects. The female cones break up when ripe to expose the red seeds, which are eaten by the Knysna turaco and the trumpeter hornbill; the birds digest the fleshy coat and regurgitate the seed, so dispersing it (PlantZAfrica).

Conservation status and regulation

Encephalartos altensteinii is listed as Vulnerable (VU) on the IUCN Red List under criterion A2acd, that is, for a past reduction of the population. The assessment, by J. D. Bösenberg, is dated 28 May 2020 and was published in 2022 (The World List of Cycads, GBIF, Crossref).

PlantZAfrica, drawing on the Red List of South African Plants, reports a decline of 30 to 50% in the wild population over a hundred years and about 10,000 mature plants remaining. The removal of large plants for gardens is the main cause, with resort development and harvesting for traditional medicine adding to it. The IUCN cycad action plan (Donaldson, 2003) already listed it as Vulnerable (A2cd), with 8,000 to 10,000 plants, a slight decline, threats from over-collecting, habitat loss and traditional use, and part of the populations in reserves. It cites one of the largest cases of illegal collecting in South Africa: more than 300 trunks removed to decorate a casino.

Like every species in the genus, it has been listed in CITES Appendix I since 4 February 1977 and is in Annex A of the EU wildlife trade regulations (current list: Regulation (EU) 2026/1383), according to Species+. For artificially propagated plants from South Africa, Species+ shows a positive EU opinion in force since 20 June 2011, limited to plants with a caudex no more than 15 cm in diameter, and a new consultation on the whole genus opened on 16 September 2026. Any plant offered for sale must come from cultivation with the required CITES documents. Databases consulted in October 2026; check the current rules before buying or importing.

Growing Encephalartos altensteinii

Encephalartos altensteinii is one of the easiest cycads to grow. PlantZAfrica describes it as a long-lived plant that adapts to most conditions provided the soil drains well and it is not exposed to heavy frost. It grows in sun or light shade, with shorter leaves in full sun. Regular watering and a feed in early summer keep it healthy. PlantZAfrica warns against automatic irrigation systems, whose jets damage leaves and trunks and lead to overwatering. Large plants transplant well provided all the leaves are removed first, which makes them easier to handle and reduces water loss. Young plants make good container specimens; adults need a large garden.

Outdoor and in-ground cultivation

Outdoors it suits frost-free or almost frost-free gardens with very free-draining soil, where its size can develop. On the French forum Fous de palmiers several members consider it fast for an Encephalartos: a plant in a conservatory near Agen produced on average two flushes of leaves each summer (2011), and another grower lists “the classic altensteinii” among the species that flush twice a year (2014). On the Mediterranean coast, a member mentioned a plant in the garden of the Plantier de Costebelle at Hyères in 2012, and the 1897 catalogue of plants grown outdoors at the Hanbury garden at La Mortola, on the Italian Riviera, already lists it, as does that of 1912.

Container cultivation

Young plants do well in a large, deep container of free-draining compost, in sun or light shade, and can be moved under glass in winter where frost is likely. PlantZAfrica’s warning applies especially to pots: avoid overwatering, particularly in cool weather. Growth of the trunk is slow: according to Live Science, the Kew plant has grown only about 2.5 cm (1 in) a year.

In cultivation in the UK, US and Australia

United Kingdom: Kew’s Palm House plant of 1775 is recorded by Guinness World Records and by Deloso et al. (2025). The Royal Botanic Garden Edinburgh, Glasgow Botanic Gardens, RHS Garden Wisley, Birmingham Botanical Gardens and two other British gardens declare the species to BGCI PlantSearch; none of these listings documents outdoor cultivation.

United States: Montgomery Botanical Center, in Coral Gables, Florida, lists several accessions in its online catalogue (numbers 9348, 64764, from 1964, and 97980 to 97982, from 1997, the year being read from the number), and Fairchild Tropical Botanic Garden lists it in its Garden Explorer. The Huntington, Lotusland and San Diego Botanic Garden in California, San Diego Zoo, Naples Botanical Garden in Florida, the UC Berkeley Botanical Garden and some seventeen other American gardens declare it to BGCI; such a listing shows that a garden has declared the species, not that the plant is alive today.

Australia: the census of the Royal Botanic Gardens Victoria records thirteen plants in twelve outdoor beds at Melbourne Gardens. The Adelaide Botanic Garden, James Cook University in Townsville and one other Australian garden declare it to BGCI.

Propagation

Encephalartos altensteinii is grown from seed, which needs plants of both sexes and, in collections, hand-pollination; plants that cone near other species may give hybrid seed. It also produces suckers at the base of the trunk (PlantZAfrica), which can be detached and rooted. Palmer and Pitman (1972), quoted by the Gymnosperm Database, report an observation by Marloth: trunks left for four years in a shed took root and produced new leaves the summer after they were planted. No sowing protocol specific to the species has been published. Seeds and plants fall under CITES Appendix I.

Pests and diseases

No disease or pest specific to Encephalartos altensteinii is described. As with other Encephalartos, the main risk in cultivation is rot of the roots and trunk in soil that stays wet in cold weather; PlantZAfrica also mentions damage from irrigation jets.

Cold hardiness

Encephalartos altensteinii tolerates light frost but is not a cold-climate species: frost is rare in its range (PlantZAfrica). Reports from cultivation show foliage damaged from about −4 °C (25 °F) and losses in France at −6 or −7 °C (21 or 19 °F), whereas in a North Carolina garden defoliated plants survived much harder cold. As for all Encephalartos, survival in cold conditions often concerns young plants whose caudex is still underground, protected by the thermal inertia of the soil and sometimes by snow; adults with a trunk above ground have no such protection and are less tolerant.

Mediterranean and European experience

On the French Riviera, a grower in Carqueiranne (Var, France) reports on the Fous de palmiers forum in January 2011 that the foliage of the species is killed at −4 °C (25 °F), the trunk being able to withstand more; he gives neither the winter nor the growing conditions. In Roussillon, a grower reports on the same forum that after four nights of frost, one of them at −5 °C (23 °F), in December 2009, his plant was undamaged. In November 2010 he wrote that he had lost an Encephalartos natalensis and an Encephalartos altensteinii at −7 °C (19 °F), without naming the winter, and in August 2026 that a plant had died in his garden “the first winter” at −6 °C (21 °F).

In Italy, a visitor to the Ottone garden near Portoferraio, on the island of Elba, reported on the Tropicamente forum in May 2012 a plant in the ground whose foliage had been scorched, “probably by frost”, after the winter of 2011–2012, without a recorded temperature. No observation of this species has been published by the Jardin zoologique tropical in the Var.

For gardeners in comparable climates, such as coastal California, southern Australia or the mildest parts of the Mediterranean, these reports suggest that young and established plants can be grown outdoors where frost is light and brief, in very free-draining soil, and that repeated frosts around −6 to −7 °C are risky.

United Kingdom, United States and Australia

In North Carolina (United States), the Juniper Level Botanic Garden in Raleigh published in August 2014 a list of the cycads that had survived in the ground, without protection or mulch, minimums of −13 to −16 °C (9 to 4 °F) depending on the site during the winter of 2013–2014: Encephalartos altensteinii was among them, but almost all the plants on the list had lost their foliage. The article gives neither the age nor the size of the plants. A grower in Roussillon commented on the Fous de palmiers forum in August 2026 that such results transfer poorly: in his view, a cycad defoliated every winter cannot last.

No USDA zone is published for the species by a botanical source. In Britain it is grown under glass; the outdoor plants at Melbourne and the American gardens of southern Florida and coastal California give no published cold data.

Toxicity and precautions

No toxicity study has been published specifically for Encephalartos altensteinii, but PlantZAfrica classes it among poisonous plants. The risk is documented in the genus: the toxicity of Encephalartos horridus was demonstrated as early as 1944 (Van der Walt), and cycads contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a toxin of the liver and nervous system; the seeds are the most dangerous part. Palmer and Pitman (1972), quoted by the Gymnosperm Database, note that in the East London district some people believed the seeds to be edible, but this has never been shown to be safe. Wear gloves to handle seeds, and keep plants and seeds out of reach of children and pets. If any part is swallowed, contact a poison centre, a doctor or a vet without delay.

Traditional uses

Encephalartos owe their name to the bread made from the pith of their trunks: Lehmann (1834), after Thunberg (1775), reports that local people roasted it to eat, and PlantZAfrica describes a preparation by fermentation in the ground, followed by baking in the ashes. These accounts concern the genus, not this species in particular. For Encephalartos altensteinii, PlantZAfrica lists harvesting for traditional medicine among the causes of its decline, and the IUCN action plan (Donaldson, 2003) describes the practice, which involves stripping bark from the trunks, in the Eastern Cape and KwaZulu-Natal. Today its main use is ornamental.

Frequently asked questions

Is Encephalartos altensteinii frost-hardy?

Only slightly. Its foliage is killed at about −4 °C (25 °F), and growers in southern France have lost plants at −6 and −7 °C (21 and 19 °F). Defoliated plants have survived much lower temperatures in North Carolina, but that is not a sound basis for planting outdoors in cold regions.

Is it the oldest pot plant in the world?

The plant at Kew is. According to Guinness World Records, it was brought from South Africa and planted in 1775, and it is displayed in the Palm House.

How do I tell it from Encephalartos natalensis?

By the base of the leaves. In Encephalartos natalensis the leaflets are reduced to several spines on each side of the leaf stalk; in Encephalartos altensteinii they get smaller without becoming spines. In the wild, the former lives inland, the latter mainly near the coast.

How big does it get?

Large. Its trunks reach about 4 m, rarely 7 m, and its leaves 1.5 to 3 m. It may branch at the base and form a clump of several trunks.

Is it fast-growing?

Yes, for an Encephalartos. Growers often see two flushes of leaves a year in warm conditions, but trunk growth remains slow: the Kew plant is said to have grown only about 2.5 cm (1 in) a year.

Is it endangered?

Yes. The IUCN lists it as Vulnerable: the wild population has fallen by 30 to 50% in a century, mainly because large plants were removed for gardens and because of coastal development.

Are the seeds poisonous?

They must be assumed to be. Claims that they are edible have never been shown to be true, and the seeds of other Encephalartos are poisonous. Keep them out of reach of children and pets.

Can I buy one legally?

Yes, if the plant comes from cultivation and has the required CITES documents. The species is in CITES Appendix I and in Annex A in the European Union.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Lehmann, J.G.C. (1834). Encephalartos altensteinii. Allgemeine Gartenzeitung 2(11): 85; and Novarum et minus cognitarum stirpium pugillus 6: 11, plates 4–5. Hamburg. [Original description.]
  • Thunberg, C.P. (1775). In: Nova Acta Regiae Societatis Scientiarum Upsaliensis 2: 284 and 287. [The name “broodboom” and the preparation of Encephalartos bread, according to Lehmann (1834).]
  • Dyer, R.A. (1965). The cycads of southern Africa. Bothalia 8: 405–515. [Description, range, hybrids, distinction from Encephalartos natalensis and Encephalartos longifolius.]
  • Palmer, E. & Pitman, N. (1972). Trees of southern Africa. A.A. Balkema, Cape Town. [Names, seeds, vitality of trunks, according to the Gymnosperm Database.]
  • Wrinkle, G. (1983). Portrait of a species: Encephalartos horridus; Encephalartos altensteinii. The Cycad Newsletter, July 1983.
  • Donaldson, J.S. (ed.) (2003). Cycads. Status Survey and Conservation Action Plan. IUCN/SSC Cycad Specialist Group, Gland and Cambridge. [Status table, threats, ex situ collections.]
  • Deloso, B.E., Colligan, A., Sucher, R. & Ramirez, V. (2025). Missouri Botanical Garden’s cycad collection: a journey through time. Plant Species Biology. https://doi.org/10.1111/1442-1984.12509 [The Kew plant as the living type specimen, at Kew since 1775; peer-reviewed article.]
  • Van der Walt, S.J. (1944). Recent investigations into the toxicity of plants, etc., in the Union of South Africa. Onderstepoort Journal of Veterinary Science and Animal Industry 20(1). https://repository.up.ac.za/handle/2263/59542 [Toxicity of Encephalartos horridus.]
  • Bösenberg, J.D. (2022). Encephalartos altensteinii. The IUCN Red List of Threatened Species 2022: e.T41908A50823149. [Assessment cited by The World List of Cycads and Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. [Etymology, via The World List of Cycads.]
  • Calonje, M., Stevenson, D.W. & Osborne, R. (2026). The World List of Cycads, version 2026.08.15. Montgomery Botanical Center, Coral Gables. https://doi.org/10.5281/zenodo.21958524 [Reference checklist.]