Cycas Revoluta - Ancient & Modern

Tony turns the spotlight on Cycas revoluta - the Sago Palm. Why is it called 'revoluta'? Why is it called 'Sago'? Why is it called a palm? And is it really hardy? Tony reveals all.
Tony King, 34 Keats Avenue, Romford, Essex
Chamaerops No.22, Spring Edition 1996

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Photo: Cycas revoluta in Barcelona, Spain

I guess that many readers will be familiar with 'The Sago Palm', Cycas revoluta, which, of course, is not a true palm at all but a member a plant family of ancient lineage: the Cycads. Sooner or later it's a fair bet that even the most modest collector of botanical exotica will discover this wonderful, architectural plant and fall in love with its appearance and unique history.

Ancient History And Wild Origins

Cycads are a group of plants that can trace their origins back directly to plants that thrived on earth at the time of the dinosaurs. Whilst it would be incorrect to say that they are unchanged from those times, they do still retain characteristics considered primitive when compared to most other living plants.

Cycas revoluta originates from the southern tip of the Japanese island of Kyushu, and the Ryukyu islands which include Okinawa and Iriomote. Here they mostly occupy nearvertical limestone cliffs around the coast or more rarely on forest floors. lt is odd that many species of cycad grow on such steep sites, as a number of Encephalartos species I was fortunate to see in habitat in South Africa were perched on cliff ledges. As for our Revoluta's, they naturally experience a very harsh environment, battered by sea gales laden with salt spray, drought and occasional snow. Temperatures vary greatly, given the wide distribution of the islands that make up its home. These can average 7°C in winter to around 33°C in summer, though as mentioned, snow can be a feature in some areas. Recent estimates put the wild populaton at around several hundred thousand throughout its distribution.

Appearance

A picture paints a thousand words and I trust the accompanying photographs give you a clear impression of the appearance of this attractive plant. What the illustration cannot convey, to those who are not familiar with the species, is the hardness of the leaves. Almost as though they are made from a tough plastic, truly 'moulded' by the harsh conditions experienced in habitat. For all this toughness, the individual leaflets are quite susceptible to damage. Should they be accidentally 'bent' the one vein supplying the leaflet with moisture will be broken and the leaflet dies, changing colour from a lovely dark green to straw yellow. Too much rough treatment can therefore result in an unsightly plant, as the leaves themselves may persist for many years. Normally, however, if you have a plant that has many damaged leaves, you can cut them all off cleanly, (in spring would be best), and this usually results in a new flush of fronds being produced in response to the harsh treatment, in a very short space of time.

New leaves are very soft and emerge from the crown of the plant. In young specimens they are often only produced in small numbers but once older and more settled a new 'flush' of 30 or more leaves is more normal. These unfurl quite rapidly and the plant benefits from extra moisture and feeding during this period. Until they have fully unfurled and 'hardened off' they remain extremely delicate and easily damaged. Additionally, if a plant producing new fronds is moved at this time the leaflets twist out of shape resuIting in a plant of poor appearance. New growth does not occur every year in most individuals and it is common for them to retain older leaves for some years,which often fade in colour. To make up for this, when new growth does occur, it is often accompanied by a significant addition to stem height and girth, resulting in an noticeably larger plant. lt is actually from the rolled, or revolute, margins to the leaflets, unique among Cycads, that this species gets its name.

The trunk itself is very starchy inside and covered in the dead leaf bases on its outer surface. The stem apex is often very woolly in appearance with a number of sharp bracts, almost as protection for the tender growing point below. Young plants have a small candex' which gradually increases as the plant grows to form the tubby trunks of more mature plants. Some plants in cultivation have stems over 3m tall, though this is rare. Plants produce suckers at the base and offsets along the trunk, sometimes prolifically, and these often give the plant the appearance of a clump. Branching is very rare, resulting perhaps from damage to the growth point at some stage.

The roots are very fleshy, and often special, upward growing, root nodules appear near to the soil surface. These are home to blue! green algae which produce essential extra nutrients for the cycad and they should never be removed.

like all species of Cycad, specimens of Cycas revoluta are either male or female. Unless you have a plant propagated from a sucker of an individual of known sex, it is unlikely you will ever discover the gender of your plant. This can only be determined when it produces cones, (cycads do not flower), and this is something only large, established specimens tend to do. Cones emerge from the top of the plant, instead of leaves. In the male this resembles a tall pine cone some 70cm long, the scales that comprise it opening on maturity to shed pollen. The female cone I can only describe as resembling a giant, furry cabbage! lt is comprised of large, ragged, leathery scales, covered in a felt-like material and packed closely together a tan/brown in colour. lt is a stumning sight! Within the cone scales of the female structure lie the large, red! orange seeds. From pollination these take around two months to mature and are then of a similar size to a walnut. Once the seeds are ripe, the cone begins to fall open and gradually disintigrate. In habitat, the seeds are believed to be distributed by birds. Often, a plant that has coned will take a rest from leaf production for a year or so, but having restored its spent energy, a new flush of foliage will emerge through the remnants of the old cone structure.

Cultivation

Not surprisingly, such an ornamental plant has been in cultivation for a very long time, especially in its homeland of Japan. Here many forms are known, including those with variegated foliage . The plant can even be successfully grown as a bonsai. It is the worlds most popular cycad and is produced, probably by the many million, by the nursery trade in many temperate areas.

lt is a tolerant species in cultivation, if somewhat slow in growth, with individuals living to a great age and old, larger specimens attracting quite high prices. For those of use in the colder, northerly latitudes, it makes a great subject for pot cultivation. A gritty, well drained compost is the one essential, as the fleshy roots will rot if the plant is overwatered. I prefer a compost based on loam, to which some peat or coco-fibre is added amid plenty of grit. I find the plants tolerant of underpotting, but a new, slightly larger container every few years in line with growth will undoubtedly give you better results. I water the plant well during the summer and apply a standard houseplant fertilizer at normal strength from late spring to early autumn. Even if the plant does not produce new foliage at this time, the food is being stored inside it and will go towards a bigger, better flush of growth when it does.

Cycas revoluta makes a good houseplant, tolerant of dry air and shadier conditions in the home, though a position in good light is better. Leafshine is not needed, just the occasional dusting! lt is ideal in the conservatory and I have found it tolerant of bright sunshine. A spell outdoors in summer is also good for cleaning up your plant. If pot grown, a winter minimum of around 5°C is adequate, provided the plant is kept more on the dry side at the roots. If kept warmer, more moisture should be given but don't keep the plant wet at this time.

The only pests I have found to trouble this plant are mealy bug and scale . Control can be time consuming, but systemic insecticides work well. If under glass you can of course try natural pest control too. Propagation is from fresh seed at around 25°C or removal and rooting of basal! stem suckers over bottom heat, but it's easier to go out and buy yourself a nice plant of this species, and save yourself time!

And Outdoors?

The species is hardy outdoors for our friends in Southern Europe around the Mediterranean. There are many beautiful and large clumps in this area, often seen in cone. Several wonderful examples were on view, even in public parks, during the 1994 European Palm Society meeting in the South of France.

Away from this region, I have seen plants growing in South West France at Combo Les Bans and I understand plants grow happily in the botanic garden at Brest. These climates of course, much cooler and wetter in winter than the Riviera coast. Experimentation in the UK is still at an early stage though both Martin Gibbons, in his London garden and Richard Darlow in his Yorkshire garden have planted out specimens which have survived so far. Myself, I have only tried a young plant, in a dry position, which failed to survive its first winter, but I'm sure a larger one would have had a better chance. If the opportunity arose I would try again with a bigger plant.

This is a wonderful plant with great potential for our region and even if you are not disposed to experiment, it will make a beautiful and long term addition to your potted collection and I highly commend it to you.

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