Cycas cairnsiana

Cycas cairnsiana is a small cycad with intensely blue foliage, endemic to the Newcastle Range, a granite massif in the dry interior of north-eastern Queensland, Australia. A species of the genus Cycas, it was described as early as 1876 by Ferdinand von Mueller and named after William Wellington Cairns, Governor of Queensland. Its very narrow, rolled, waxy blue leaflets make it one of the most sought-after of Australia’s “blue cycads”, and also one of the slowest and most demanding in cultivation. For decades its name was wrongly applied to another species, Cycas platyphylla. The IUCN lists it as Near Threatened.

Key facts about Cycas cairnsiana

  • Accepted name: Cycas cairnsiana F.Muell. (1876), according to The World List of Cycads; POWO could not be consulted directly
  • Former names and synonyms: no synonym; horticultural names reported: Cycas sp. ‘Mt Surprise’, Cycas sp. ‘Champions Blue Surprise’
  • Family: Cycadaceae
  • Common names: “Mt Surprise Sago”, the label used by the Royal Botanic Garden Sydney and the Australian Botanic Garden Mount Annan; no other English name attested
  • Natural range: Australia, north-eastern Queensland, around the Newcastle Range (Mount Surprise and Forsayth areas)
  • IUCN status: Near Threatened (NT); assessed by K. D. Hill (2010, criteria B2a; D2, according to The World List of Cycads), reassessed by J. D. Bösenberg in Red List version 2023-1, NT according to GBIF
  • CITES: Appendix II (listing of the whole family); Annex B in the European Union
  • Documented hardiness: no value measured in a controlled way; one reported benchmark, no leaf damage at −5.4 °C (22.3 °F) in Arizona in the winter of 2010–2011 (see Cold hardiness)
  • Light and soil: full sun; very free-draining sandy and gravelly granite soils in the wild
  • Habit and adult size: trunk up to 2 m, rarely 5 m, 12 to 16 cm across; leaves 60 to 110 cm long
  • In the UK, US and Australia: Kew; Montgomery Botanical Center (accessions from 1994 to 2024) and several other American gardens; Royal Botanic Garden Sydney and Mount Annan (wild-collected plants) and six other Australian gardens
  • Toxicity: not studied for the species; all parts of Cycas are poisonous (see Toxicity and precautions)

How to recognise Cycas cairnsiana

Cycas cairnsiana is recognised by its leaflets only 2 to 3 mm wide, with margins strongly rolled under, and by its pale, waxy blue foliage, which keeps its colour for the whole life of the leaf. No other Australian species combines these characters. The description below follows that of K. D. Hill (1992), based on plants from both known populations:

  • Trunk: up to 2 m tall, rarely 5 m, 12 to 16 cm across.
  • Leaves: 60 to 110 cm long, strongly keeled (the leaflets of the two sides form a V at an angle of 30 to 90°), with 180 to 280 leaflets; petiole hairless, 18 to 27 cm long.
  • Leaflets: 80 to 180 mm long by 2 to 3 mm wide (rarely 4 mm), hairless, very waxy, pale blue, with strongly recurved or rolled margins; midrib raised beneath.
  • New growth: covered with thick, loose orange-brown down that does not persist; cataphylls (the scales protecting the growing point) slender, with bright orange down.
  • Male cones: ovoid, 16 to 20 cm long and 7 to 10 cm across.
  • Megasporophylls (the fertile leaves of female plants): 16 to 21 cm, orange-brown down, carrying 2 to 4 ovules; blade narrowly triangular, 40 to 70 mm by 15 to 25 mm, regularly toothed.
  • Seeds: ovoid, green turning yellowish, covered with a thick white bloom, 36 to 42 mm long.

Plants from the Forsayth population have slightly broader leaflets than those around Mount Surprise (Hill 1992). Paul Forster (2001) stresses that the blue colour is particularly intense and lasts for the whole life of the leaf, whereas related species lose their blue tint as the leaves age.

Hybrids

No natural hybrid is documented. In cultivation, members of the French forum Fous de palmiers have grown hybrids of Cycas thouarsii × Cycas cairnsiana since about 2009, sought to combine the fast growth of the former with the blue colour of the latter; several growers report clearly faster growth than in pure Cycas cairnsiana. The origin of these seeds is not stated in the messages consulted.

Possible confusion

The main confusion is historical: until 1992, botanists and nurserymen alike applied the name Cycas cairnsiana to the plants of Petford, on the Atherton Tableland, which K. D. Hill described as Cycas platyphylla. That species has broader leaflets (4 to 6 mm) with margins only recurved, and bluish foliage that turns yellowish as it ages. The other “blue cycads” of Queensland also have broader leaflets: Cycas couttsiana (4.5 to 6 mm, persistent white down), Cycas cupida (5 to 7 mm, leaflets not narrowed at the base) and Cycas desolata (3.5 to 5 mm, petiole without spines). De Laubenfels and Adema (1998) also compared it with Cycas pruinosa, a bluish species of Western Australia and the Northern Territory.

Taxonomy

Cycas cairnsiana is accepted by The World List of Cycads; POWO could not be consulted. Ferdinand von Mueller described it in 1876 in his Fragmenta Phytographiae Australiae (volume 10, pages 63 and 121), from collections made by William Armit in the Newcastle Range. The holotype is in the National Herbarium of Victoria in Melbourne (MEL), with isotypes in London (BM) and at Kew (K).

In K. D. Hill’s classification (1996), all the Australian species belong to section Cycas, subsection Endemicae. Cycas cairnsiana is the type species of series Cairnsianosae, which brings together species of north-central Queensland with keeled, strongly bluish leaves: Cycas cairnsiana, Cycas couttsiana, Cycas desolata, Cycas ophiolitica, Cycas platyphylla and, since 2001, Cycas cupida. Hill (1996) describes in this group the anatomy of a plant of dry habitats: a continuous layer of protective cells beneath the epidermis, stomata sunk in deep pits and a very thick cuticle. Montgomery Botanical Center, in 2025, speaks of a “Cycas cairnsiana group” of five pale-blue species (without Cycas ophiolitica) whose morphological similarities make identification difficult, and is collecting DNA to clarify the boundaries between them.

Etymology and history

The epithet honours Sir William Wellington Cairns (1828–1888), fourth Governor of Queensland (Haynes 2022, taken up by The World List of Cycads). The exact locality of Armit’s collection, noted as “heads of the Robinson and Percy rivers”, long remained unknown; K. D. Hill traced it and matched the type with the plants of O’Briens Creek, near Mount Surprise (Hill 1992).

The name has had an eventful history. In the Philippines, Merrill first applied it in 1923 to the cycad of Culion Island, later described as Cycas wadei (Lindström et al. 2008). In Australia it was used for years for the plants of Petford, now Cycas platyphylla (Hill 1992). Two articles in The Cycad Newsletter of 2012 are devoted to it, one on growing it in Arizona (Argyros; Anderson); they could not be consulted directly.

Common names

The Royal Botanic Garden Sydney and the Australian Botanic Garden Mount Annan label the species “Mt Surprise Sago” in their online catalogues; this is a garden label, not a name with a documented vernacular use. No Aboriginal name could be verified. The Palm and Cycad Societies of Australia (PACSOA) cite two horticultural names, Cycas sp. ‘Mt Surprise’ and Cycas sp. ‘Champions Blue Surprise’, used before the identity of the Mount Surprise plants was established.

In the wild

Cycas cairnsiana is endemic to Queensland, Australia. K. D. Hill (1992, 1996) knew it from only two extensive, scattered populations around the Newcastle Range, in the dry interior of the north-east of the state, near Forsayth and Mount Surprise. The plants grow on shallow to skeletal, sandy and gravelly soils derived from siliceous granite. PACSOA describes colonies among large granite boulders in open woodland; that text, however, also cites the Petford and Chillagoe areas, where Cycas platyphylla actually grows, and must be read with caution.

The French nurseryman Simon Lavaud (2021), using published climate averages for Mount Surprise, notes that temperatures there do not fall below 10 °C (50 °F), that daytime temperatures exceed or approach 30 °C (86 °F) for much of the year, and that the hottest months are the wettest while the coolest are dry, with about 800 mm of rain a year. He adds that the species generally grows on very rocky soils.

Conservation status and regulation

The World List of Cycads gives Cycas cairnsiana the category Near Threatened (NT, criteria B2a; D2) and cites K. D. Hill’s assessment for the 2010 Red List. A reassessment by J. D. Bösenberg was published in Red List version 2023-1 (reference checked on Crossref), and the IUCN data relayed by GBIF give the NT category (consulted on 21 October 2026); the Red List itself could not be consulted. As early as 1992, K. D. Hill noted that, although both populations are large, neither is protected and the plant’s spectacular appearance exposes it to heavy collecting pressure for the trade. In 2025 Montgomery Botanical Center wrote that the global demand for the pale-blue Cycas of this group has led to significant population declines through the collection of plants and seeds.

Like every species of the family Cycadaceae, Cycas cairnsiana is listed in CITES Appendix II. Species+, the official CITES and EU database, shows this listing at family level, with annotation #4 (version in force since 5 March 2026): seeds, pollen and seedlings or tissue cultures obtained in vitro in sterile containers are exempt, but live plants remain subject to permits. Australia, the United Kingdom and the United States apply CITES through their own national legislation; in the European Union the species is in Annex B of Regulation (EC) No 338/97, in the version set by Commission Regulation (EU) 2026/1383. Check the rules in force before any purchase, import or sale, and ask for proof that the plant is cultivated. This information does not replace the official texts.

Growing Cycas cairnsiana

In short: a difficult species for experienced growers. Published data and growers’ reports agree on three points: it needs a great deal of heat, a perfectly drained substrate and a dry winter, and it grows very slowly. PACSOA recommends a hot, dry, very well-drained position and describes it as sensitive to high humidity; this advice should be weighed against the uncertain identity of the plants it describes.

Outdoor and in-ground cultivation

In warm climates it is grown in botanic gardens: Montgomery Botanical Center, in South Florida, whose cycad collection is grown outdoors, holds 19 accessions, and the Royal Botanic Garden Sydney lists one of its wild-collected plants in a numbered garden bed (whether outdoors or under cover is not stated). Its natural soils, very rocky and fast-draining, are the model to follow.

For Mediterranean-type climates, the European experience gathered on French and Italian forums is mostly one of failures under winter rain, and no lasting outdoor planting is documented in Europe. In California, southern Australia or other regions with wet, cool winters, the same reversal of the seasons applies: by simple deduction, any outdoor trial would need a site sheltered from winter rain and a mineral, very fast-draining soil; no such trial has been found in the sources consulted.

Container cultivation

In Europe and in the United Kingdom, it is a plant for a pot under glass. Simon Lavaud (2021) rates it “difficult” among Australian Cycas and recommends for the group a very mineral substrate (pumice or other volcanic rock), full sun or the brightest place in the glasshouse, a glasshouse to lengthen the growing season, generous and frequent watering when nights reach 18 to 20 °C (64.4 to 68 °F) and days 30 °C (86 °F), reduced watering below 20 °C (68 °F) and none when nights drop below 10 °C (50 °F), because of the very high risk of root rot.

The experience of European growers, mostly in Mediterranean climates comparable to those of California or southern Australia, confirms this:

  • On the French forum Fous de palmiers, a grower from Belley (Ain) and Montpellier (Hérault) explains in 2017 that the species dislikes winter damp, needs a heated glasshouse, and takes two to three years for an imported plant to re-root.
  • A grower on the Côte Bleue, near Marseille, observed in January 2010 that his three-year-old plant lost its foliage every December in cooler conditions, while a second, younger plant kept its leaves.
  • A grower in Poland noted in 2012 that seedlings sown in 2008 and grown in pots had produced only a few leaves and seemed to need more heat than Encephalartos.
  • On the Italian forum Tropicamente, a grower from Ravenna (Emilia-Romagna, Italy) lost seedlings and young plants to rot several times between 2009 and 2015, although they were in a very free-draining mix and wintered frost-free on a veranda; another Italian grower reported excellent germination of seed from Australia followed by successive losses, which he attributed to an unsuitable substrate.

The site’s article on the Simon Lavaud method, which grafts blue Australian Cycas onto Cycas revoluta to protect them from root rot, names Cycas cairnsiana among the Australian blue cycads and as a logical candidate for future trials; it reports no grafting result for this species.

In cultivation in the UK, US and Australia

In short: present in many botanic gardens, often from wild-collected material, but with very few published growing results.

  • United Kingdom: the Royal Botanic Gardens, Kew, declares the species in BGCI PlantSearch (consulted in October 2026); where it is grown at Kew is not stated.
  • United States: the online catalogue of Montgomery Botanical Center (Coral Gables, Florida) lists 19 accessions, whose numbers show entries in 1994, 2004, 2019, 2022 and 2024 (one database annotation on the record points to Cycas media, which calls for caution). In 2025 the garden reported that it had collected more than 1,800 seeds of Cycas cairnsiana, Cycas cupida, Cycas desolata and Cycas platyphylla in northern Queensland; half are being raised in Australia and half are now in its living collections, to build assurance colonies. The Huntington (San Marino, California), Naples Botanical Garden (Florida), the University of California Botanical Garden at Berkeley, Boyce Thompson Arboretum (Superior, Arizona), Edison and Ford Winter Estates (Fort Myers, Florida), Honolulu Botanical Gardens, Moore Farms Botanical Garden (Lake City, South Carolina) and the University of Minnesota conservatory also declare it in BGCI.
  • Australia: the Royal Botanic Garden Sydney lists six accessions of wild provenance (1990, 1994, 1995, 2021 and 2022), one of them in bed 65h; the Australian Botanic Garden Mount Annan lists two (2022 and 2024), both from the wild (online catalogues updated in October 2026). Brisbane Botanic Gardens Mount Coot-tha, the Australian National Botanic Gardens in Canberra, the Botanic Garden of Adelaide, James Cook University in Townsville, Noosa Botanic Gardens and the North Coast Regional Botanic Garden in Coffs Harbour declare it in BGCI.

The only published growing account from these countries is the Arizona article of 2012 (see Cold hardiness), known only from a forum summary. PalmTalk and Dave’s Garden, where American growers discuss the species, could not be consulted.

Propagation

Propagation is from seed. A grower on the Fous de palmiers forum reports that about six seeds out of ten germinated, even after the shell was accidentally opened, and a grower in Ravenna had three seeds out of five germinate in 2014. Seedlings are very slow: another forum member reports plants sown in 2008 that still had only one leaf, or none, in 2010. No published germination data specific to the species have been found.

Pests and diseases

Root and trunk rot in a cold, wet substrate is the cause of failure most often reported by European growers. Simon Lavaud (2021) shows beetles feeding on the emerging leaves of Cycas cairnsiana in Thailand (photograph of 2019). Like all Cycas, the species is exposed to the Asian cycad scale, Aulacaspis yasumatsui; no data specific to the species have been found.

Cold hardiness

No controlled measurement exists. The only published benchmark comes from Arizona, and European experience shows that winter wet is a greater danger than cold itself.

European experience

No result of open-ground cultivation has been found in Europe, and no minimum temperature tolerated there is documented. French growers on the Fous de palmiers forum keep it in pots, under glass or indoors; a member from Batz-sur-Mer, in Brittany, finds it far from easy to grow there. In Ravenna (USDA zones 8a–8b according to the grower), a young plant in a pot, sheltered from rain and wind, appears in a 2009 list of cycads that had withstood down to −3 °C (26.6 °F) outdoors, without the date of the episode being given; the same grower later lost several plants to rot. This Mediterranean and northern Italian experience is useful to growers in comparable climates, such as coastal California, southern Australia or the mildest parts of southern England, but it points to pot culture, kept dry and frost-free in winter.

United Kingdom, United States and Australia

  • A grower in Arizona (United States) reports in The Cycad Newsletter (Anderson 2012), according to the summary given by a grower from Roussillon on the Fous de palmiers forum, that his plants suffered no leaf damage during the winter of 2010–2011, with a minimum of −5.4 °C (22.3 °F) and eight days of frost, and that they take summers above 43 °C (109.4 °F); whether they were in the ground or in pots is not stated. The original article could not be read.
  • PACSOA describes the species as frost-tolerant without giving a value; the statement is not quantified and may partly concern Cycas platyphylla.
  • No USDA zone can be given on the basis of a documented trial.

Toxicity and precautions

No toxicity data specific to Cycas cairnsiana have been found, but the risk is well documented in the genus: Cycas tissues, and the seeds above all, contain cycasin, which is converted during digestion into methylazoxymethanol, toxic to the liver and nervous system, along with a neurotoxic amino acid, BMAA. The ASPCA lists the sago palm as poisonous to dogs, cats and horses, with vomiting, sometimes bloody diarrhoea, jaundice and liver damage that can be fatal; NC State Extension notes that cycasin is present in all parts of the plant.

Wear gloves to handle the seeds and their fleshy coat, pick up any that fall, 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 straight away.

Traditional uses

No traditional use specific to Cycas cairnsiana has been found in the sources consulted.

Frequently asked questions

Why is Cycas cairnsiana blue?

Because its leaflets are covered with a thick layer of wax. Like the sunken stomata and very thick cuticle, this wax is a feature of the Cycas of the dry, sunny habitats of Queensland.

Is Cycas cairnsiana hardy?

No, not as an outdoor plant in the UK or most of Europe. The only published benchmark is the absence of damage at −5.4 °C (22.3 °F) in Arizona, in a very dry climate; in wet-winter climates it is grown in a pot, dry and frost-free in winter.

Why is my young plant rotting?

Most often because of a cold, wet substrate. Growers report many losses to rot in Europe; a very mineral substrate, sustained summer heat and a dry winter reduce the risk.

How does it differ from Cycas platyphylla?

Mainly in leaflet width. Cycas cairnsiana has leaflets 2 to 3 mm wide with rolled margins and stays blue; Cycas platyphylla has leaflets 4 to 6 mm wide, with margins only recurved, and turns yellowish with age.

Does it grow fast?

No. Growers describe it as very slow: a few leaves in several years for seedlings grown in Europe.

Can it be grafted?

Perhaps. Grafting onto Cycas revoluta has succeeded with Cycas couttsiana, according to the site’s article on the Simon Lavaud method, but it is not documented for this species.

Where can I see it in a garden?

In Australia, in the Royal Botanic Garden Sydney and the Australian Botanic Garden Mount Annan, among others; in the United States, at Montgomery Botanical Center in Florida and several other gardens; in the United Kingdom, Kew declares it.

Is it poisonous?

Yes, very probably. It has not been studied, but all parts of Cycas are poisonous, especially the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Mueller, F. von (1876). Fragmenta Phytographiae Australiae 10(83): 63, 121. [Original description; reference taken from The World List of Cycads, text not consulted.]
  • Hill, K.D. (1992). A preliminary account of Cycas (Cycadaceae) in Queensland. Telopea 5(1): 177–206. doi:10.7751/telopea19924964 [Typification, full description, range and status of the species; full text consulted.]
  • Hill, K.D. (1996). A taxonomic revision of the genus Cycas (Cycadaceae) in Australia. Telopea 7(1): 1–64. doi:10.7751/telopea19963040 [Revision of the Australian species, series, leaf anatomy, range; full text consulted.]
  • de Laubenfels, D.J. & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Revision with a broad species concept; full text consulted.]
  • Forster, P.I. (2001). Cycas cupida (Cycadaceae), a new species from central Queensland. Austrobaileya 6(1): 153–160. doi:10.5962/p.299661 [Key to series Cairnsianosae and remark on the persistent blue colour; full text consulted.]
  • Lindström, A.J., Hill, K.D. & Stanberg, L.C. (2008). The genus Cycas (Cycadaceae) in The Philippines. Telopea 12(1): 119–145. doi:10.7751/telopea20085805 [Misapplication of the name to the Culion plants by Merrill; full text consulted.]
  • Argyros, N. (2012). Cycas cairnsiana. The Cycad Newsletter 35(1): 10–15; Anderson, R.C. (2012). Growing Cycas cairnsiana in Arizona. The Cycad Newsletter 35(1): 16. [Journal of The Cycad Society; references taken from The World List of Cycads, texts not consulted.]
  • Hill, K.D. (2010). Cycas cairnsiana. The IUCN Red List of Threatened Species: e.T41972A10614004. doi:10.2305/IUCN.UK.2010-3.RLTS.T41972A10614004.en [Previous assessment (NT, B2a; D2 according to The World List of Cycads); reference checked on Crossref.]
  • Bösenberg, J.D. (2023). Cycas cairnsiana. The IUCN Red List of Threatened Species 2023: e.T41972A67337917. doi:10.2305/IUCN.UK.2023-1.RLTS.T41972A67337917.en [Current assessment; reference checked on Crossref, NT category relayed by GBIF; page not consulted (access blocked).]
  • Montgomery Botanical Center (2025). The search for Australia’s blue cycads. Montgomery Botanical News 33(1), spring–summer 2025. [Seed collecting in northern Queensland, threats from collection; full text consulted.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology of the epithet; cited by The World List of Cycads, text not consulted.]
  • Calonje, M., Stevenson, D.W. & Osborne, R. (2026). The World List of Cycads, version 2026.08.15. Montgomery Botanical Center, Coral Gables. doi:10.5281/zenodo.21958524 [Reference checklist: accepted name, original publication, type, range, synonyms, IUCN status; consulted directly.]