Encephalartos laevifolius — the Kaapsehoop cycad

Introduction

Encephalartos laevifolius  is a tall, slender cycad with even, regular, smooth leafbases. It grows well in full sun and tolerates any soil type, provided the soil is well drained and aerated. It is a relatively slow grower, but very frost-hardy and drought-resistant. Like all cycad species, it prefers moderate watering.

Description

Encephalartos laevifolius has tall stems, often reaching 3 to 4 metres in height. The trunks are comparatively slender for a cycad of this height with diameters usually 25-30 cm. Older stems are often prostrate with the growing ends curving upwards. The leaf bases are small and compressed, giving a characteristic appearance to the trunk. A banding pattern is usually fairly clear, and probably indicates alternations in growing conditions or coning cycles. When there is little or no woolliness at the stem apex, the sharp, upward-pointing and persistent scale leaves are clearly visible.

The leaves are up to 1.5 m long, bluish-green with a silvery bloom on the upper side and a slightly lighter green on the lower side. The petiole is about 60-250 mm long and yellow. Leaves are straight and stiff, but they curve gradually downwards and are often slightly twisted near the apex. Young leaves have a dense white woolly outer layer which disappears at maturity. The median leaflets attain a length of up to 100-150 mm and a width of 5-7 mm, and are leathery without nodules. The undersurfaces have 10-12 parallel nerves which are clearly visible. At the base, the leaflets are reduced in size, and spineless.

Male and female plants bear 1-5 yellow-green cones per season per stem. Cones are at first covered with short whitish hairs, which are soon lost to give the final smooth pale brown appearance. The male cones are 300-430 x 80-115 mm and curve sideways at the time of pollen shedding. The female cones are about 400-450 x 150-190 mm. The cones are produced in May with the male cones shedding pollen during September-November, and the female cones starting to disintegrate during January-March, releasing 350-385 seeds per cone.

Conservation status

According to Raimondo et al  (2009), Encephalartos laevifolius is critically endangered (CR), as the available evidence indicates that it meets all of the five IUCN criteria for critically endangered, and is therefore facing a high risk of extinction in the wild.

Distribution and habitat

This cycad is endemic to South Africa and is restricted to the catchment area of the Kaapsehoop Mountains in the Nelspruit District and the Piggs Peak area of Swaziland. The plants grow on exposed rocky outcrops. In their distribution area the annual rainfall is more than 1000 mm and falls predominantly in summer.

Derivation of name and history

Encephalartos laevifolius was described in 1926 by Otto Stapf and Joseph Burtt Davy.

The specific name is derived from the Latin word laevis which means " smooth ", and refers to the smoothness of the leaflets relative to that of the leaflets of E. lanatus.

Ecology

Cycads use smells and heat to attract and repel insect pollinators. The plants heat up and produce a nasty odour that drives the pollen-covered insects out of the cones of male cycads. The female cones then attract these selfsame insects with a milder, more alluring odour. When the insects move between the sexes, they inadvertently transfer the pollen from the male cones to the receptive ovules of the female cones.

The fleshy outer covering layer of the seeds is desirable food to a range of animals such as monkeys, birds, rodents and bats. Therefore, with any luck, the seeds are discarded some distance away from the parent plant in a hospitable environment in which they are likely to germinate.

Uses

Cycads can be used as decorative or focal point plants in gardens and can also be very effective as grouped plantings. In ancient times, indigenous people used to make bread from cycad stems. However, one should note that all parts of cycads are toxic.

Growing this species

Encephalartos laevifolius  grows relatively slowly and survives well in full sun or light shade, and is very frost-hardy.  It is easily propagated from seeds and suckers (the young plants that grow around the main stem).

The seeds should be collected, cleaned and stored in a brown paper bag at 10-15 °C for six months or more, to allow the embryo to fully develop.  The seeds are cleaned to ensure that all the flesh is removed since it may contain germination inhibitors, and can also promote the growth of fungi. The flesh is scraped away with a knife but protective gloves should be worn during the cleaning operation to prevent contact with the slow-acting poisons present in the flesh.  If the flesh is hard and dry, it helps to soak the seeds in water for a day or two before cleaning.  Even if the seeds have been cleaned, it is a good idea to soak them for a few days, preferably with daily changes of water, before planting them.  When the seeds are placed in water, the viable ones will sink and the non-viable ones will float.

To germinate the seeds, place the cleaned seeds on their sides half-buried on washed sand or potting mix, and keep at about 28 °C .  It is necessary to keep the medium moist, but not too wet, for as long as it takes for germination to take place.  As soon as the radicals of the sprouted kernels are 10-20 mm long, they can be planted singly in bags containing potting soil or some other suitable medium.  Alternatively one can wait until the seedlings develop one or two leaves before transplanting them individually into bags.

Because cycad seedlings form long tap roots, it is advisable to use tall narrow perforated black plastic bags about 24x12 cm in size for their initial establishment.  Place the seedlings under shade for the first few years of growth and development.  Initially the seedlings must be watered daily with a fine spray.  After about a month, as their roots elongate, the frequency of watering should be decreased to once a week.  The seedlings can be transplanted into the garden when they are 3-5 years old.  When preparing to propagate from suckers, a hole should be dug around the stem of the mother plant to expose the base and roots of the suckers.  A clean sharp knife or sharp spade should be used to remove the sucker from the mother plant.  The wound should then be treated with a fungicide and dried for about a week before planting the sucker into a sterile medium.

Cycads are ideal for a low-maintenance garden, as they require a minimum amount of water and are undemanding in their soil and environmental needs.

Pests troublesome to cycads are scale insects, beetles and chewing insects.  Scale insects cause great damage to cycad leaves by sucking the sap from them.  Most scale insects can be controlled with regular and frequent applications of horticultural soluble oil such as white oil.  Beetles seriously damage cycad plants by attacking the emerging young leaves.  Control can be kept by application of contact or systemic insecticides, or one of the bacterial preparations available.