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This cycad has been described as the hardiest, most
drought resistant of the South African species. In the past, many
specimens of this cycad were removed from the wild for cultivation.
Description
This low-growing, small to medium cycad with an erect trunk up to
2 m tall and 400 mm across, forms clumps of up to 10 stems, with
suckers produced from the base. Old leaf bases form ring patterns
on the stem, the surface of which is papery and dry. It has beautiful
blue leaves which are 1-1.5 m long. The whorls of leaves become
entangled as the plant becomes bushy and the crowns appear to lose
individual identity.
Male
and female plants produce a single cone per stem. Male cones are
sub-cylindrical, 250-350 mm long, 80-100 mm in diameter, carried
on a short stem (peduncle), 50-120 mm long. They are bluish green,
with a covering of blackish red, fine hairs which thin out as the
cone grows, allowing the green to show through.
Female
cones are barrel-shaped, 450-500 mm long and approx. 250 mm in diameter.
They are similar in colour to male cones, if slightly darker. They
also have distinct, slightly 'warty' ridges separating otherwise
smooth facets of cone-scales and a covering of fine, brownish 'hair'.
Seeds are deep red in colour.
Coning occurs every two years if sufficient rain falls,
but may cease during prolonged droughts. Seeds are capable of germinating
even if only occasional light mists occur to provide moisture.
This plant is endemic to the interior of Eastern Cape in South Africa
where it grows in the catchments of several rivers. Its habitat
is semi-arid with an annual rainfall around 250 - 350 mm. Rain falls
mainly in summer, but rainfall is very erratic and this cycad can
survive prolonged droughts. It is found mostly on sandstone hills,
mountain slopes, but occasional clusters can be found on hard, open
ground at the edge of dry watercourses. This region is very hot
in summer and cold in winter with frequent frosts. Plants grow in
full sun and are often surrounded by thorn scrub species of aloe
and euphorbia. The surrounding vegetation is not as prone to fire
as some grasslands.
Specific name
This cycad is named in honour of Professor J.G.C. Lehmann, a nineteenth
century German botanist who described several cycad species in 1834
and established the genus Encephalartos.
Growing Encephalartos lehmannii
This cycad is easy to cultivate. It is an extremely
hardy and attractive species with excellent ornamental qualities.
It requires neutral to alkaline soil with very good drainage. If
grown in shade and with too much moisture, the leaves will lose
their metallic blue colour and will turn green, so plant it in a
sunny position. It is suited to temperate regions including those
with a semi-arid climate and tolerates moderate to heavy frosts.
Do not over-water.
Propagation: From seed and by removal of suckers which
transplant readily.
Pests: to be on the lookout for in southern Africa:
Leaf parasites range from moth larvae to plant lice and can all
be rather well controlled with contact insecticides. Cone parasites,
mostly beetles or weevils, attack the cones of both male and female
plants and can cause great destruction. Spray the cones with insecticide
just before the cones become sexually mature and for some weeks
after. Be very careful before spraying: make sure the beetles on
the plants are actual pests and not pollinators.
Stem/trunk and root parasites: larvae from certain
beetles have been known to infiltrate the trunks of cycads causing
rot to set in, which if untreated, can kill the cycad. Treat with
a systemic insecticide and in addition, carefully cut out any infected
trunk tissue, then sterilize and seal the trunk to stop any fungal
and bacterial infection.
Certain ant and termite species are known to attack
the roots and the underground part of the trunk, causing damage
and leaving the plant vulnerable to fungal and bacterial infections.
Various insecticides are available on the market to combat these
problem insects.
Various fungicides are available to fight fungal infections.
Infected and even old dry leaves should be removed and burned to
stop any remaining spores from germinating. Bacterial infections
are a more difficult matter and up to date, nothing on the market
has proved to be really effective.
For information on pests in the rest of the world,
please contact your nearest nursery or cycad expert.
Legislation relating to growing /owning cycads in South Africa
REFERENCES
- GIDDY, C. 1974. Cycads of South Africa. Purnell,
Cape Town.
- GOODE, D. 1986. Cycads of Africa. Struik, Cape Town.
- GOODE, D. 2001. Cycads of Africa, vol. 1. D & E Cycads
of Africa, Gallomanor.
- GROBBELAAR, N. 2002. Broodbome. Met spesiale verwysing na die
Suider-Afrikaanse soorte. Pretoria.
- HILTON-TAYLOR, C. 1996. Red Data List of southern African plants.
Strelitzia 4. National Botanical Institute, Pretoria.
- JONES, D.L. 1993. Cycads of the World: ancient plants in today's
landscape. Reed, New South Wales.
- KREMPIN, J. 1990. Palms and cycads around the World. Horwitz
Grahame, Australia.
Lou-Nita Le Roux
Lowveld National Botanical Garden
April 2003
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