endangered member of the protea family was once common on the Cape
Flats, but has been reduced by urban development to a few populations
along road verges, inside horseracing tracks and under powerlines.
Unless there is appropriate management of the survival of this species,
these few remaining populations will become extinct in the wild.
Description and ecology
Leucadendron levisanus is an erect, 2 m tall, well-branched
shrub developing from a single stem at ground level. The slender
branches bear very small oblanceolate to spoon-shaped leaves. Leucadendrons
are dioecious, i.e. separate male and female plants. The male flowerhead
bears bright yellow flowers with a faint sweet odour. These flowers
can cover the entire plant to produce a beautiful flowering display
in spring and early summer. The mature female flowerhead forms globose
cones. These cones retain the seed, a small, hard-shelled nut, 3-4
mm long, until environmental conditions are conducive for the seed
to be released. This normally happens after a fire. This species
first flowers after 3 years and is mature at the age of 10 years
and senesces at 30 years.
Distribution and habitat
levisanus once occurred in huge stands on the Cape Peninsula
from Paarden Island to Kommetjie. The Cape Flats conebush grows
well in acid, sandy soils. The species experiences wet soils during
the winter period and the soils are normally dry and loose during
the hot and windy summer months. L. levisanus survives better
if there is a good, closely growing diverse community of species
growing in a relatively undisturbed area. These plants form a good
symbiotic relationship by protecting each other to form a natural
vegetation cover that keeps the soil cool and binds the sandy soil
as well. Plants found in this community are
Diastella proteiodes (Flats silkypuff), Leucospermum
hypophyllocarpodendron (green snake-stem pincushion), Erica
mammosa (ninepin heath), Serruria fasciflora (common
pin spiderhead), S.
aemula (strawberry spiderhead) and restios (Cape reeds).
The genus Leucadendron belongs to the protea family and derives
from the Greek word leukos meaning white and dendron
meaning tree, referring to the silver tree, L. argenteum
on which the genus was based. The common name Cape Flats conebush
presumably refers to it being found growing on the Cape Flats area.
It is not clear whether the specific name levisanus is a
Latin reference to someone by the name of Lewis, or whether it refers
to the light habit of the plant or the smooth leaves.
This plant is endangered due to extensive urbanization around Cape
Town, resulting in the destruction of its habitat. Changes to the
habitat by altering the drainage system to suit urban development,
water pollution, illegal dumping and a lack of fire management threatens
the last remaining populations.
Heavy infestations of alien Acacia species in the natural
growing area of the Cape Flats conebush have affected populations.
Management of the alien vegetation through brush cutting and spraying
of herbicides, pose serious problems for the future of the remaining
populations. These populations are either wrongly removed or are
damaged by spray drift from the herbicides.
Growing Leucadendron levisanus
levisanus is reproduced from tip and heel cuttings taken in
spring and autumn. Cuttings are rooted in a 50:50 mixture of fine,
milled pine bark and polystyrene balls. Applying a rooting hormone
will stimulate rooting. Rooting can take place from 6 weeks onwards.
Rooted cuttings are removed from the mist benches and hardened off
for 3 weeks before being potted. Rooting can only take place if
you have sufficient underfloor heating and mist benches set up in
a good propagation greenhouse. The rooted cuttings are potted in
a soil medium made for fynbos plants. A suitable mixture would consist
of sand, composted pine bark and loam or topsoil. The potted cuttings
should be grown in a well-ventilated and lit area and should be
watered in the morning. They could be fed every second week with
an organic-based, seaweed fertilizer.
The young plants should be planted in early autumn or just after
the first winter rains. This will allow the root system to become
strong and established before the hot, dry summer months. It is
a tall shrub so plant it behind other smaller shrubs and bedding
plants in your garden. The plants need to be planted in full sunlight
and ensure the soil is well drained. Mulching with woodchips or
compost during summer will keep the soil cool and help feed the
plants. Although the plant produces seed, it however, has not been
grown from seed before in cultivation.
INITIATIVES TOWARDS SURVIVAL
In situ conservation
The main remaining populations occur under power lines managed by
Eskom. This particular area was given National Heritage Site Status
because there are other threatened Cape Flats flora growing on it.
Representatives from Eskom, Cape Nature Conservation, Kirstenbosh,
Botanical Society and professional conservation biologists have
worked towards establishing appropriate land management practices
to ensure the survival of the remaining populations.
Ex situ conservation
Plants are currently being propagated and grown at Kirstenbosch
Botanical Gardens. Representatives of Kirstenbosch, Tygerberg Nature
Conservation and Eskom recently re-introduced these plants into
the damaged areas under the power lines. Staff from Kirstenbosch
gave a small demonstration as to how to plant this species without
any damage to the plant or the surrounding environment. Plants are
also grown for display in the garden of extinction at Kirstenbosh
Gardens. This is a theme garden displaying plants that are extinct
in the wild or close to becoming extinct. Plants are also available
at rare plant fairs in April and October.
- Jackson, W.P.U. 1990. Origins and meanings of names of South
African plant genera. University of Cape Town.
- Rebelo, A.G. (Tony). 2000. Proteas of the Cape Peninsula.
Protea Atlas Project, National Botanical Institute, Cape Town.
- Rebelo, A.G. 1995. Sasol proteas. A field guide to the proteas
of southern Africa. Fernwood Press, Cape Town.
- Vogts, M. 1982. South Africa's Proteaceae. Know them and
grow them. Struik, Cape Town.