SCELETIUM is a small genus of low growing
succulent shrubs in the ice plant family (Aizoaceae) endemic to the
karroid areas of Western, Eastern and Northern Cape Provinces, South
Africa. The succulent leaves grow in pairs and eventually die away
leaving persistent leaf vein skeletons clothing the lower stems,
which protect the plants from adverse environmental conditions. The
small flowers vary in color from white to yellow and occasionally
pale orange or pink.
Most of the species are practically unknown in cultivation and
endangered in habitat. Plant gatherers in South Africa have observed
that wild populations of Sceletium tortuosum are becoming
increasingly scarce, possibly due to over collection. Protection
through cultivation is encouraged.
Starting off
Sceletium is easily grown, and seeds are sprouted much the same as
any common cacti. Mature plants also root easily from
cuttings. Sceletium can become weedy if over-watered and overfed.
Some species are tolerant of mild frost, but it's best not to bring
them outdoors until the last frost has passed.
Growing on
The soil should be allowed to dry out between watering if
growing in a pot. Obviously the size of the pot is a
variable where this is concerned but as long as the plant body
remains firm looking with no signs of wrinkling, then resist the
temptation to over-water. Make this judgment on cooler days; during
very hot and sunny periods, most plants will have a tendency to
wrinkle especially if they are in a greenhouse. If in doubt....don't
is the rule.
Watering kanna is something of a balancing
act....too little and the plants become stunted....too much and they
rot or, at best, they start making new bodies at the wrong time of
year (if this happens stop watering until the first body has been
consumed by the new). After a year or two you will get to know how
the plants behave in your particular situation......experience is
the best teacher.
So, water sparingly until shoot and root growth is well established.
Then increase watering and apply a well-balanced liquid feed
periodically. Good light is essential so that plants produce strong,
sturdy growth. Ideally maintain a minimum temperature of 16ºC or
60ºC, although
plants will tolerate cooler conditions. Any general purpose
compost with some added grit to help drainage is suitable or any of
the propriety cactus composts is ideal. An occasional feed as for
houseplants is permissible but don't over do it, Sceletium plants
require little in the way of nutrients.
Planting out and aftercare
The planting site should be open and sunny and the soil
can be enriched with general cactus soil or compost as was used when
they were in a pot. Space Kannas some distance apart because they
creep along the ground, much like plants that propagate through
rhizomes, and they can take up a lot of ground space in a short
amount of time when cared for properly.
Overwintering
After the first frosts lift the rhizomes and move them to a
frost-free glasshouse or shed. Ensure plants are properly labeled.
Pack the roots in pots, covered with compost or bark, and keep them
just moist throughout the winter.
When you receive seedlings
Take great care with unwrapping - new shoots at this stage are
extremely fragile, and a shoot broken off represents a lost
flowering shoot. Kanna has a lot of water content, and in
travelling, they can become dehydrated and less pliable.
The seedlings should be immediately potted up, irrespective of the
time of year. Use any general purpose cactus soil, and place the
pots in a light airy frost-free place. A cool greenhouse with heat
only when frost threatens is ideal. Keep the compost slightly moist
(not dry, not over-wet), until the growing season starts.
If immediate potting is impractical, the seedlings should be covered
in damp peat. Kanna seedlings do not normally enter a totally dormant
stage, and if they are thoroughly dried out, then some will
be lost. (This is perhaps one reason why Kannas are not
often sold in garden centers - they do not appreciate being kept for
long periods in a handful of dry sawdust in pre-packs - many are
lost leading to complaints).
If the Kanna are intended for indoor cultivation, then they may be
potted up immediately and grown on under heat.
As with many rhizomatous plants, not every seedling will grow (Kanna
growers are happy with an 80% success rate), although some will throw up 2 or 3 shoots.
Pests and diseases
In the spring, newly emerging shoots should be sprayed for aphids,
though aphids are not often a problem with grown plants.
Young plants should be protected from slugs and snails which ignore
the open leaves but have a preference for the newly unrolling
leaves. A single nibble at this stage by a slug will cause a
disfiguring row of holes as the leaf unfurls that will remain with
the plant for several months. Older plants are not often troubled by
slugs and snails.
Red Spider Mite can occasionally infest indoor Kanna. The symptoms
are dry-looking leaves which turn uniformly brown. When examined
closely on the underside, such leaves show traces of a white powder
(which is the dried egg-cases) particularly near the central leaf
rib, and myriads of extremely tiny creatures all running around. You
really need a magnifying glass to see them. To answer a common
query, Red Spider Mites are not often red in color. Red Spider Mite
is immune to most if not all proprietary preparations available to
the amateur. Soap-based insecticides combined with a powerful spray
can dislodge and/or suffocate them, and minimize the problem to an
acceptable level.
Kanna virus disease is more widespread than is commonly appreciated.
It is initially recognized by pale colored spots and streaks in
leaves, and by distorted or "crinkly" leaves. Later, badly affected
plants show dead rust-colored streaks in the leaves, throughout the
plant, and the growth is badly stunted. The plant may still flower,
but the flowers may have a distorted shape with white patches.
Little is known about Kanna virus - some plants are badly affected
and may die of their own accord, or remain badly stunted, but other
plants show only a mild infection of one or two leaves and seem to
be able to recover. There is no cure for virus disease, and plants
that are obviously diseased should be dug up and destroyed.
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