Encephalartos longifolius

Encephalartos longifolius, known as Thunberg’s cycad or the Suurberg cycad, is a large South African cycad endemic to the south-western Eastern Cape, where it grows in the mountains from the Kouga range, west of Joubertina, to the Suurberg (Zuurberg) and the Grahamstown (Makhanda) district. This species of the genus Encephalartos, described in 1801 by Nikolaus Joseph von Jacquin as Zamia longifolia, forms a massive trunk that can exceed 4 m, topped by a crown of dark green leaves curving down like an umbrella. Its female cones, which can weigh 36 kg, are among the heaviest of all South African cycads. With Encephalartos caffer, it was one of the first two southern African cycads collected by a botanist, Carl Peter Thunberg, in 1772. Listed as Near Threatened by the IUCN, it is still well represented in the wild, partly in protected areas. In cultivation it is a popular, sun-loving garden cycad, with blue and silver forms much sought after.

Key facts about Encephalartos longifolius

  • Accepted name: Encephalartos longifolius (Jacq.) Lehm. (1834), accepted by The World List of Cycads (version 2026.08.15), GBIF and Species+
  • Former names and synonyms: Zamia longifolia Jacq. (1801, basionym); Zamia lanuginosa Jacq. (1801) and Encephalartos lanuginosus (Jacq.) Lehm. (1834); Encephalartos mauritianus Miq. (1842); several varieties described by Miquel and Regel (1842, 1874)
  • Family: Zamiaceae, order Cycadales
  • Common names: Thunberg’s cycad and Suurberg cycad (PlantZAfrica, Species+); Suurbergbroodboom in Afrikaans (PlantZAfrica)
  • Natural range: South Africa, south-western Eastern Cape (Kouga, Baviaanskloof, Groot Winterhoek and Klein Winterhoek mountains, Suurberg, Grahamstown district), at 200 to 1,500 m
  • IUCN status: Near Threatened (NT), assessment by J.D. Bösenberg dated May 2020, published in 2022
  • CITES and other protection: CITES Appendix I (whole genus, since 1977); Annex A in the European Union, with a positive EU opinion (2011) for artificially propagated plants from South Africa with a caudex up to 15 cm in diameter
  • Documented hardiness: mature plants may tolerate light frost (PlantZAfrica); a blue form raised from seed did not survive −13 to −16 °C (9 to 4 °F) in North Carolina in winter 2013–2014; no measured value published for the plants grown outdoors in Mediterranean Europe (see Cold hardiness)
  • Light and soil: full sun for mature plants; moderately acid, well-drained sandy loam (PlantZAfrica)
  • Habit and adult size: upright stems up to about 4.5 m, 30 to 45 cm across, often single but up to ten from the base; leaves 1 to 2 m
  • In the UK, US and Australia: Kew (BGCI); Montgomery Botanical Center (13 accessions), the Huntington, Lotusland, Marie Selby, Naples Botanical Garden and others in the United States; outdoor beds at the Royal Botanic Gardens Victoria, Sydney, Adelaide and Cairns in Australia
  • Toxicity: seeds poisonous; a poisoning of a Boer commando in the Suurberg is documented (see Toxicity and precautions)

How to recognise Encephalartos longifolius

It is a large, tree-forming Encephalartos with a massive trunk and a crown of glossy dark green leaves whose last third curves strongly downwards, giving a fairly compact umbrella shape. Dyer (1965) and PlantZAfrica describe it as follows:

  • Stems: usually upright, up to about 3 m (Dyer), rarely 4 to 5 m, or up to 4.5 m (PlantZAfrica), 30 to 45 cm across; often single, but up to ten stems may arise from the base; according to Dyer, branching above ground is abnormal, probably caused by injury
  • Leaves: 1 to 2 m, sometimes almost straight but usually spreading and curved towards the tip; finely hairy when young, then hairless
  • Leaflets: usually dark green, sometimes with a bluish sheen or bloom, overlapping in the upper half of the leaf; the median ones up to 20 cm long and 4 cm wide, with a pungent or rounded tip, almost always entire or with one to three small teeth on the lower margin; towards the base they become smaller without being reduced to more than one or two prickles. Lehmann described them as “lanceolate, acute, unarmed, quite entire, green”
  • Cones: one or two per stem according to Dyer, brownish green with close-pressed russet hairs; up to three male cones per plant according to PlantZAfrica, 40 to 60 cm by 14 to 20 cm, with scales drawn out into a beak of about 2 cm; one female cone, rarely two, olive green, ovoid, up to 60 by 40 cm, with coarsely wrinkled scales; they are among the heaviest of South African cycads, a female cone weighing up to 36 kg (PlantZAfrica)
  • Seeds: red, about 5 by 2.5 cm (Dyer, 1965)

Dyer notes that the stature, the metallic green colour and the scaly hairs of the leaflets usually identify the species, but that the bloom varies so much that some plants have a silvery sheen. Jungle Music, a cycad nursery in Encinitas, California, describes leaf colours ranging from lime green to powdery silver, stacked leaflets, plants that may be armed or completely unarmed, and trunks 20 to 30 inches (51 to 76 cm) across, wider than the botanical descriptions; these blue and silver forms are much sought after in cultivation.

Encephalartos longifolius
Encephalartos longifolius grown at the Villa Thuret, Antibes, on the French Riviera.

Hybrids

Natural hybrids with Encephalartos horridus are reported where the two species grow together: Guy Wrinkle wrote in 1983, in a species portrait published by The Cycad Society (United States), that he had seen “very beautiful” ones in the Eastern Cape. The wiki of the Palm and Cycad Societies of Australia (PACSOA) describes plants in the Suurberg with lobed leaflets, the lobes rounded, which it interprets as the trace of ancient hybridisation with Encephalartos horridus, citing the work of Cynthia Giddy. On the other hand, Dyer (1965) states that no hybridisation has been reported with Encephalartos lehmannii, which grows alongside it at Paardepoort. In cultivation, hybrids with Encephalartos latifrons are offered by at least one specialist nursery (Exclusive Cycads, 2026); as with all cycads, a plant raised from garden seed is not necessarily pure.

Possible confusion

The most frequent confusion is with Encephalartos altensteinii, its closest relative according to Dyer (1965). Its leaflets carry one or two teeth, sometimes three to five, on one or both margins, whereas those of Encephalartos longifolius are almost always entire; but a plant of Encephalartos altensteinii grown in full sun can cause doubt. In the wild the two ranges do not overlap: Encephalartos longifolius occupies the inland hills, on Table Mountain sandstone, Encephalartos altensteinii mostly coastal bush and cliffs further east. The famous potted plant at Kew, brought back in 1775 by Francis Masson, who travelled with Thunberg, was long taken for an Encephalartos longifolius; it is now identified as Encephalartos altensteinii (PACSOA wiki).

Thunberg himself confused the species with a small, underground-stemmed Encephalartos collected on the same journey, Encephalartos caffer, which he took for its juvenile form (Dyer, 1965; PlantZAfrica). Its umbrella-shaped crown sometimes recalls that of Encephalartos woodii: Dyer advises checking for the absence of small prickles at the base of the leaves. In Encephalartos natalensis, another large green species often grown, the leaflets at the base of the petiole are by contrast reduced to a series of prickles; it grows further north-east, in KwaZulu-Natal. Finally, Encephalartos lehmannii, which sometimes shares its sites, is smaller, with stiff, almost straight, clearly blue leaves and narrower, more widely spaced leaflets.

Taxonomy

Encephalartos longifolius is an accepted name in The World List of Cycads, GBIF and Species+. Its history begins with a confusion: in 1772, Carl Peter Thunberg, travelling down the Langkloof valley with Francis Masson, collected a tree-forming species and a dwarf species that he took for two forms of the same plant; he described them in 1775 as Cycas caffra, which became Zamia caffra in 1800 (PlantZAfrica; Dyer, 1965). In 1801 Jacquin, who had plants grown at Schönbrunn, separated the large species as Zamia longifolia (Fragmenta botanica: 28, plate 29). Lehmann transferred it to Encephalartos on 15 March 1834, in the Allgemeine Gartenzeitung (volume 2, no. 11, p. 86), then in the sixth part of his Novarum et minus cognitarum stirpium pugillus. The name Encephalartos caffer was eventually kept for the dwarf species (Dyer, 1965).

The World List of Cycads places in synonymy Zamia lanuginosa Jacq. (1801), which Lehmann had transferred in 1834, in the same work, as Encephalartos lanuginosus, separating it by its woolly trunk and leaflets with two spiny teeth, as well as Encephalartos mauritianus Miq. (1842) and three varieties described by Miquel (angustifolius and revolutus, 1842) and Regel (latifolius, 1874). No variety is recognised today. For the reader, this means that old collection plants may bear any of these names.

Etymology and history

The epithet comes from the Latin longus, “long”, and folium, “leaf”: the leaves are long compared with those of Encephalartos caffer, described in the same work (Haynes, 2022, cited by The World List of Cycads). The genus name means “bread in the head”, because bread was made from the pith of these plants in their homeland (Lehmann, 1834).

The species was grown early in Europe: according to Dyer (1965), the Viennese gardener and collector Scholl brought back plants, together with those of Encephalartos horridus and Encephalartos cycadifolius, for the imperial garden at Schönbrunn, where Jacquin described them. For travellers reaching the Eastern Cape through the Langkloof, it was the first Encephalartos to be seen (Dyer, 1965).

Common names

PlantZAfrica gives the English names Thunberg’s cycad, in honour of the botanist who first collected it, and Suurberg cycad, after the Zuurberg range, together with the Afrikaans name Suurbergbroodboom; Species+ cites both English names. The name “long-leaved cycad”, sometimes seen, is only a translation of the epithet.

In the wild

Encephalartos longifolius is endemic to the south-western Eastern Cape, in South Africa. Its range starts west of Joubertina, in the Kouga Mountains, continues along the Kouga and Suuranys mountains, the eastern Baviaanskloof Mountains, the Elandsberg and part of the Groot Winterhoek Mountains, then, after a gap, in the Klein Winterhoek Mountains, the Zuurberg and, further east, the Grahamstown district (PlantZAfrica). Dyer (1965) describes it as an imposing feature of the sourveld mountains, from the Uniondale to the Albany districts. With Encephalartos lehmannii, it is the westernmost cycad in South Africa, and the ranges of the two species overlap slightly (PlantZAfrica).

The species occupies very varied habitats, between 200 and 1,500 m, with 300 to 1,250 mm of rain a year:

  • acid sands with fynbos vegetation west of Port Elizabeth (Gqeberha);
  • grassland in the Zuurberg;
  • succulent thicket near Kirkwood and at Paardepoort, which PlantZAfrica places in the Klein Winterhoek Mountains and Dyer on the Klein Winterberg.

Its trunks long withstand the fierce fires of the fynbos; Dyer wondered whether fire had set the western limit of the species. The PACSOA wiki describes, in the Suurberg, plants in full sun on north-facing slopes, in tall grass, on clay soil kept well drained by the slope.

Cones appear from April to June and seeds fall from October to December; pollinating beetles have been found on wild cones, although their role has not been proven for this species. The seeds are dispersed by baboons, hornbills and small rodents, which eat their fleshy coat (PlantZAfrica).

Conservation status and regulation

Encephalartos longifolius is listed as Near Threatened (NT) on the IUCN Red List: it is close to the thresholds of criteria A2ad (population reduction) and B1ab(v) (small range, decline in mature individuals). The assessment, by J.D. Bösenberg, is dated 29 May 2020 and was published in 2022 (The World List of Cycads, GBIF, Crossref).

The IUCN cycad action plan (Donaldson, 2003) already listed it as Near Threatened, with 7,000 to 15,000 plants, a low rate of decline, over-collection as the threat and minor habitat loss; it had been considered Vulnerable in 1997. According to PlantZAfrica, the main threat is illegal collection, but many populations lie in protected areas: the Baviaanskloof reserve, the Groendal Wilderness Area, the Longmore State Forest and the Addo Elephant National Park (Zuurberg). The species remains well represented in the wild, and nurseries offer cultivated plants. SANBI has published no non-detriment finding document for it.

Regulation, according to Species+ (consulted through its public API on 26 October 2026):

  • CITES: Appendix I since 4 February 1977, like the whole genus;
  • European Union: Annex A, current list in Regulation (EU) 2026/1383; for artificially propagated plants from South Africa, the EU Scientific Review Group issued a positive opinion on 20 June 2011, limited to plants with a caudex up to 15 cm in diameter, still in force; a new consultation covering the whole genus has been open since 16 September 2026.

These notes do not replace the official texts: check Species+ and EUR-Lex before any purchase or import, and ask for documents proving that a plant was propagated in cultivation.

Growing Encephalartos longifolius

PlantZAfrica presents Encephalartos longifolius as a fine feature plant for the garden, also suitable for containers, suited to temperate and cool subtropical regions. Mature plants prefer full sun. The soil should be a moderately acid, well-drained sandy loam; too much water encourages root rot, which can spread to the whole plant if it is not stopped in time. PlantZAfrica recommends regular feeding with a balanced inorganic fertiliser and a mulch of compost or manure.

Outdoor and in-ground cultivation

Jungle Music writes, on an undated page, that the species is a full-sun plant for most of California, needing partial sun or filtered light only in extreme desert heat, a soil that drains well and a slightly acid pH; it describes it as fast-growing, making one or two flushes of leaves a year depending on culture, adaptable to tropical, Mediterranean and desert-type gardens, and best placed in the foreground of a planting, where it can be appreciated.

In Mediterranean Europe, the Villa Thuret, the botanical garden of Antibes, grows at least four plants in the ground (Fous de palmiers forum, 2009–2013; photograph above), and the fact sheet written by INRA’s Villa Thuret for the Hanbury Botanical Gardens states that the species can be seen in both gardens. In Italy, the Palermo Botanical Garden lists “several remarkable specimens” outdoors in its Cycadetum, and a grower photographed a plant in the ground in the giardino dell’Ottone, on the island of Elba, in May 2012 (Tropicamente forum). The Naples Botanical Garden held seven plants of different ages and sexes, “outdoors or in glasshouses”, in 1981, and ten specimens in 1993–94 (Delpinoa). None of these records gives a minimum temperature.

Container cultivation

PlantZAfrica recommends the species for containers and gives a potting mix: four shovels of clean, coarse river sand, four of milled pine bark and two and a half of loam, with 40 g of dolomite or dolomitic lime, 3 g of iron sulphate and a balanced slow-release fertiliser. Water moderately, never letting the mix stay wet. A pot allows the plant to be moved under cover in cold winters; the other French reports on the Fous de palmiers forum concern plants in pots (Lot-et-Garonne, 2010) or seedlings under glass, without data on cold.

In cultivation in the UK, US and Australia

In Britain, the Royal Botanic Gardens, Kew, declares the species to BGCI PlantSearch; no other British garden does, and Kew’s famous old cycad, long called Encephalartos longifolius, is in fact an Encephalartos altensteinii (PACSOA wiki). In the United States, Montgomery Botanical Center in Coral Gables, Florida, holds thirteen accessions in its online catalogue, several of them received in 1994, 1998 and 1999 according to their numbers; Ganna Walska Lotusland, the Huntington, Descanso Gardens, the Los Angeles County Arboretum, the San Diego Botanic Garden, the San Diego Zoo and its Safari Park, the University of California Botanical Garden at Berkeley, the US Botanic Garden, Marie Selby Botanical Gardens, Naples Botanical Garden, Moore Farms Botanical Garden and several Hawaiian gardens declare it to BGCI. Jungle Music reports that it usually has a hundred or more plants in stock, including a blue form. In Australia, the Royal Botanic Gardens Victoria grows Encephalartos longifolius in outdoor beds at Melbourne Gardens, according to its online census, and the Royal Botanic Garden Sydney, the Botanic Garden of South Australia in Adelaide and the Cairns Botanic Gardens declare it to BGCI. A BGCI listing shows that a garden has declared the species at some point, not that a plant is alive today.

Propagation

Encephalartos longifolius is propagated mainly from seed. PlantZAfrica gives the method used in South Africa:

  • soak the seeds in water for a few days to remove their fleshy coat, wearing gloves because it is poisonous, then let them dry;
  • sow in spring in trays of clean river sand, kept at 25 to 28 °C (77 to 82.4 °F);
  • germination is spread over three to six months, after which the seedlings are carefully lifted and potted into bags of a well-drained mix;
  • at about two years, plant them in large pots or in the garden.

Basal suckers can also be removed. Seeds, plants and suckers fall under CITES Appendix I.

Pests and diseases

In cultivation, the main pests are mealybugs and scale insects, which PlantZAfrica treats with systemic insecticides. Snout beetles attack the cones and often destroy the seeds, and a tiny gall midge lays its eggs on emerging leaves, which it can destroy; PlantZAfrica recommends a contact insecticide whenever new leaves appear. In temperate climates, the main risk remains root rot in cold, waterlogged soil.

Cold hardiness

According to PlantZAfrica, mature plants may tolerate light frost. Dated reports are very rare, and the only published result with temperatures is a failure. As with all Encephalartos, survivals in cold areas often concern young plants whose caudex is still underground, protected by the thermal inertia of the soil; an adult with an aerial trunk, like this one, has no such protection.

Mediterranean and European experience

No temperature record has been published for the plants of the Villa Thuret, nor elsewhere in France, and none for the plants of Palermo, La Mortola or Elba. Their presence in the ground on the French and Italian Riviera and in Sicily shows that the species is grown in the open in these mild Mediterranean climates, which resemble those of coastal California or southern Australia, but no figure can be drawn from them. No report is documented for Atlantic or inland Europe.

United Kingdom, United States and Australia

At the Juniper Level Botanic Garden, in North Carolina, a blue form raised from seed did not survive winter 2013–2014 in the ground without protection, with minimums of −13 to −16 °C (9 to 4 °F) depending on the site; Encephalartos lehmannii and Encephalartos princeps did not survive either. In Melbourne, the plants in outdoor beds show that the species is grown in the open in a temperate Australian climate, without a published cold record. No British outdoor report has been published, and no botanical source gives a USDA zone for the species; the zone ratings found on some websites cite no measurement. In Britain, a cool, bright glasshouse is the safe choice.

Toxicity and precautions

The seeds of Encephalartos longifolius are poisonous, and PlantZAfrica reports a famous poisoning: during the Anglo-Boer War (1899–1902), men of General Jan Smuts’s commando, besieged in the Zuurberg and short of food, tried its seeds; they were soon in agony, but by the next morning most had recovered and were able to march on into the mountains. Encephalartos contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a toxin of the liver and the nervous system; the seeds are the most dangerous part. The ASPCA reports vomiting, diarrhoea, liver damage and deaths in dogs, cats and horses that have eaten cycads.

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

According to PlantZAfrica, the inhabitants of the region once used cycad stems as food: the pith was scooped out and buried to ferment, which possibly broke down the toxins, then dried and ground into flour for cakes baked on the fire. The INRA fact sheet from the Villa Thuret describes a similar preparation for this species (pith rolled in skins for two months, then kneaded and baked under the ashes). Demand for large garden plants has led to collection from the wild (PlantZAfrica).

Frequently asked questions

Is Encephalartos longifolius frost-hardy?

Only to light frost, as far as is known. PlantZAfrica says mature plants may tolerate light frost; the species grows outdoors on the French and Italian Riviera, but no minimum temperature has been published, and a seed-grown blue form died at −13 to −16 °C (9 to 4 °F) in North Carolina. Away from mild coasts, a large pot moved under cover in winter is safer.

How do I tell Encephalartos longifolius from Encephalartos altensteinii?

Mainly by the leaflets: almost always entire in Encephalartos longifolius, toothed on both margins in Encephalartos altensteinii. The strongly recurved, umbrella-shaped crown of Encephalartos longifolius also helps, but a plant of Encephalartos altensteinii in full sun can look similar.

Is there a blue Encephalartos longifolius?

Yes. The bloom on the leaflets varies, and some plants have a bluish or silvery sheen (Dyer, 1965). Nurseries sell them as “blue form”; this is not a botanical variety.

Why are its cones so heavy?

It is a feature of the species: a female cone can reach 60 by 40 cm and weigh up to 36 kg, among the heaviest of South African cycads.

Can Encephalartos longifolius be grown in a pot?

Yes. PlantZAfrica recommends it for containers, in a very free-draining mix of coarse sand, pine bark and loam. A pot also lets the plant be brought under cover during cold winters.

Is Encephalartos longifolius toxic?

Yes, especially its seeds. The poisoning of a Boer commando in the Zuurberg during the Anglo-Boer War is well known in South Africa.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Thunberg, C.P. (1775). Cycas caffra. Nova Acta Regiae Societatis Scientiarum Upsaliensis 2. [Description mixing Encephalartos longifolius and Encephalartos caffer; cited by Lehmann (1834), Dyer (1965) and PlantZAfrica.]
  • Jacquin, N.J. (1801). Zamia longifolia. Fragmenta botanica: 28, plate 29. Vienna. [Basionym; cited by The World List of Cycads and Dyer (1965).]
  • Lehmann, J.G.C. (1834). Encephalartos longifolius. Allgemeine Gartenzeitung 2(11): 86; and Novarum et minus cognitarum stirpium pugillus 6. Hamburg. [New combination; text of the Pugillus read (diagnoses no. 8, lanuginosus, and no. 11).]
  • Dyer, R.A. (1965). The cycads of southern Africa. Bothalia 8: 405–515. [Key, description, distribution, history, distinction from Encephalartos altensteinii, Encephalartos woodii and Encephalartos caffer.]
  • Wrinkle, G. (1983). Portrait of a species: Encephalartos horridus; Encephalartos altensteinii. The Cycad Newsletter, July 1983.
  • Kemp, M. (1985). Focus on Encephalartos longifolius. Encephalartos 1: 6–13. [Members-only journal of the Cycad Society of South Africa; cited by PlantZAfrica.]
  • Gaudio, L., Aceto, S., Caputo, P., Cozzolino, S., Siniscalco Gigliano, G., Moretti, A. & De Luca, P. (1997). Enzyme polymorphism in Encephalartos Lehmann (Zamiaceae). Delpinoa n.s. 35–36 (1993–1994): 55–64. [Plants grown at Naples.]
  • Donaldson, J.S. (ed.) (2003). Cycads. Status Survey and Conservation Action Plan. IUCN/SSC Cycad Specialist Group, Gland and Cambridge. [Status table.]
  • Bösenberg, J.D. (2022). Encephalartos longifolius. The IUCN Red List of Threatened Species 2022: e.T41935A51047890. [Assessment cited by The World List of Cycads and Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. https://doi.org/10.11646/phytotaxa.550.1.1 [Etymology, cited by 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 [Checklist.]