SA TREE NO: 253
COMMON NAME:
Small Knobwood / Lemon-thorn / Wild Cardamon
OTHER NAMES:
Kleinperdepram / Parapis / Prambos / Kardamon / Knopdoring / Maagbessie / Wag-‘n-Bietjie / Lemoendoring / Knophout / Katdoring (Afr) amaBelentombi / umNungumabele (Zulu) umLungumabele (Xhosa)
FAMILY:
Rutaceae (The Citrus family)
A large family, occurring globally, but most common in warm and temperate regions, with about 160 genera and more than 2000 species of trees, woody shrubs and a few herbs, belonging to the order Sapindales. Members can be identified by the presence of aromatic oil glands on the leaves, (usually only visible as translucent gland dots when held against direct sunlight), and perfumed, bractless flowers, generally divided into 4 or 5 parts, occurring in a cyme or solitary. Most flowers are hermaphroditic, and the leaves are typically oppositely arranged, compound, and lack stipules. Several members are of economic importance, and many are planted as ornamentals.
Z.capense typically grows as a willowy, small to medium, multi-stemmed tree with a scant, rather disorderly crown of lovely, glossy leaves and attractive matt-grey bark, adorned with conspicuous, woody, spine-tipped protrusions. These are significantly sharper and stronger on young trees, but eventually become somewhat blunted and pyramid shaped as the tree matures.
HABITAT:
Naturally found in a variety of habitats, especially in the eastern and norther parts of the country, from dry bushveld and woodland, to higher altitudes, where it spreads into the mist-belt forests. The trees are often associated with rocky outcrops, but can also be found in open grassland, from the Eastern Cape, along a wide coastal belt, to Natal and Transkei, extending into Swaziland and Zimbabwe.
DECIDUOUS/EVERGREEN:
Deciduous.
BARK:
Grey to dark-grey, characteristically fortified with numerous cone-shaped knobs (20-30 mm), each capped with a short, stout thorn (8-10 mm). The stems and leaves may also occasionally be covered with short, hard, sharp prickles.
FOLIAGE:
Glossy, alternately arranged and compound (35-200 mm long), leaves, crowded together on the tips of side-growing twigs. Each major leaf comprises of 4-8 pairs of opposite to alternate leaflets (10-60 x 10-20 mm), plus a terminal leaf, which may be absent. The leaflets are dark-green above, paler below, oval to elliptic in shape, with tapering bases and somewhat rounded tips. When crushed, the leaves give off a pungent citrus aroma, and if held against bright sunlight, a scattering of minute gland dots can be observed along the finely scalloped margins. The petiole is about 10 mm long, slightly grooved or channelled above, and often has 2 tiny, hard lobes at the base.
FLOWERS:
Minute, greenish-white and faintly scented. The inflorescence is borne in petite, much-branched, terminal panicles (20-60 mm), and the sexes are carried separately, on different trees. (October – February).
FRUIT:
Miniscule, spherical berries (3-5 mm diameter), produced in large clusters, with a lovely rusty, brownish-red to orange colouring. The fruits are covered with small glands, and have a strong, slightly acrid, lemony taste that leaves a burning sensation in the mouth. They frequently remain on the tree for long periods of time, and eventually split open to half reveal a solitary, black seed. (February to May).
SEED:
Small, shiny, dark-brown to black, each containing a high amount of volatile oils.
HEIGHT:
2-15 m (in the garden it may only reach between 3-4 m)
SPREAD:
1-3 m
TOLERANCE:
Once properly established, the tree can withstand extremely dry conditions, even if they persist, and is also able to endure moderate frosts.
GROWTH RATE:
Moderate to fast, 50-70 cm per year under favourable conditions. First fruiting can be expected at about 6 years of age.
LIGHTING REQUIREMENTS:
Full sun, but light, dappled shade will also be accepted, as long as a few hours of direct sunlight are provided each day.
SOIL AND WATER REQUIREMENTS:
Loamy, well-drained, fertile soils. The trees prefer areas with warm summers and moderate rainfall. Water-wise.
ADVANTAGES:
This quirky little tree does not have an aggressive root system, and will look delightful as a trained container plant or large bonsai, even as a single specimen. The tree is hardy and versatile, and will do well even in difficult gardens. A must-have in any bird garden, and due to its somewhat small stature, it can be planted close to patios and permanent structures such as walls, paving and pools.
WILDLIFE:
The multitude of berry-like fruits attract birds, monkeys and baboons, while the flowers are pollinated by insects and beetles, which will in turn lure numerous insectivorous bird species. The leaves are occasionally browsed by smaller antelope and bush pigs. The trees are also an important food plant for several stunning Swallowtail butterfly species.
PROPAGATION:
Seeds do not germinate easily, as most of them are heavily damaged by insects, rendering them sterile. Propagation is best done by harvesting seedlings growing beneath the parent plant. After carefully harvesting, plant the young trees into a humus rich, aerated mixture of compost and river sand (2:1), place in a bright, warm area, and keep moist.
MEDICINAL:
Nearly all parts of the tree are used, from the fruits to the roots. Leaf, fruit and bark infusions are used to treat gastric and intestinal complaints, fever, colds, epilepsy and to kill intestinal parasites (one teaspoon of crushed leaves to one cup water). Traditional remedies for snakebites, either taken internally or applied topically, are made from the roots and leaves, and the fruits are used to treat colic and palsy. Powder from the pulverized roots is used to treat poisoning of the blood, and clear skin infections. Twigs and leaves are burnt, and the smoke inhaled to ease dizziness. The bark is carefully removed from the twigs, after which they are flattened and used as traditional toothbrushes. Various parts of the tree contain alkaloids, and one which is of particular significance is sanguinarine, which has been proven to effectively bind to dental plaque and inhibit future growth, even in small quantities. Bark from the roots or stem is chewed to alleviate toothache and treat oral infections and sores, and is also applied to wounds. A mouthwash is made from an infusion of the bark and powdered roots.
PRACTICAL:
The wood is yellow-brown, hard and fairly durable. It is not commonly used for furniture, but mostly for smaller implements, handles, yokes, planks and walking sticks. The roots yield a pale-brown to yellow dye. A pleasant, home-made alcoholic beverage is often made from the fruits; half-crushed, semi-ripened fruits are harvested, then soaked in cane spirits. A powerfully scented perfume is also made by soaking the fruits in water.
ADDITIONAL FACTS:
This tree has been declared as protected species in South Africa.