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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