Erythrina caffra

Trees

  • Coastal Coral Tree (E)
  • Coral Tree (E)
  • Coast Erythrina (E)
  • Lucky Bean Tree (E)
  • Cape Coral Tree (E)
  • Kuskoraalboom (A)
  • Koraalboom (A)
  • Kurkboom (A)
  • umSintsi (X)
  • umSinsi (Z)

Description

  • A magnificent, medium to large tree, with an attractive branch structure that develops numerous rounded heads to form a wide, low- spreading, umbrella or dome-shaped canopy of light green, sharp-tipped leaves. The smooth, pastel-grey bark is covered with numerous thorn-tipped knobs, and vivid scarlet to deep orange, many petalled, nectar laden flowers are produced in profusion during late winter. The flowers often open before the flush of new spring leaves, which further enhances the beauty of the trees in flower. A hardy, versatile, long lived species, able to reach ages of 150 years or more, loved all over the world for its arresting beauty and ease of cultivation.

SA Tree

  • 242

Family

  • Fabaceae or Leguminosae (Legume or pod-bearing family).
  • This family is also divided into 3 subfamilies; mimosa or acacia subfamily, cassia and pea. Regarded as one of the largest, as well as economically significant families, its members have been cultivated since early times for their plethora of uses – as food, medicine, fodder, for practical use (tannins) and ornamental displays.

Habitat

  • Most commonly found in sheltered coastal forests, wooded grassland and riverine or stream fringe forests in the warm coastal regions of the Eastern Cape and KwaZulu-Natal.
  • Occasionally, specimens have been found in swamp forests.
  • They can also be found in the extreme south of Mozambique and along the south eastern coast of South Africa, from sea-level to altitudes of about 1000 m.

Bark

  • Pale to dark grey or brownish-grey, slightly rough textured, with longitudinal fissures.
  • The trunk and branches are typically armed with stout, short thorny knobs or recurved prickles, which fade as the tree matures.
  • The main stem is generally tall, much-branched, with a naturally wide girth, even on trees that are not very tall.
  • The tree may retain some sparsely scattered, short prickles on the main, low positioned branches, and these spines can also be found on the leaves and young stems.

Foliage

  • Deciduous

  • Trifoliate, broadly ovate to elliptic, hairless, dark-green leaflets, the terminal, unpaired one being the largest (80-160 x 80-180 mm).
  • The bases of the smaller, lateral leaflets are generally asymmetric, and they are carried on short stalks, without hairs or spines.
  • The margins are entire, and the leaf tips are sharply pointed.
  • The leaves are borne on long (140 -160 mm), sometimes sparsely prickled stalks, and a pair of glands can often be seen where the stalk meets up with the leaflets.

Flowers

  • Showy, vivid scarlet-orange or occasionally cream tinged flowers, clustered towards the ends of large, thickset racemes (80-100 mm).
  • Each flower consists of about 4 smaller petals and a main, relatively short and broad standard petal that opens and curves slightly upward to expose the stamens below.
  • The flowers are carried in large, dense clusters (80-100 x 170-200 mm), at the ends of branchlets, and are often produced before the new leaves. (August-September)

Fruit

  • Long, narrow (80-200 mm), cylindrical, hairless, dark charcoal to almost black coloured pods.
  • The pods are deeply and irregularly constricted between the seeds.
  • They tend to split on the tree to reveal numerous small, glossy, coral-red seeds, each with a distinct black-spot where they were attached to the pod.
  • Over time, the seeds are inclined to lose their brilliancy and become a rich red-brown. (October-December).

Height

  • 8-12 m, occasionally reaching 20 m under favourable conditions. (The ultimate height and spread will depend largely on the climate where it is grown)

Spread

  • 6-10 m

Medicinal

  • Various extracts from Erythrina caffra displayed a number of antibacterial, anti-inflammatory and analgesic effects, and their effects were investigated against different bacterial strains.
  • All the compounds proved active against both Gram-negative and Gram-positive bacteria.
  • The alkaloids present Erythrina (particularly the seeds), are known to be highly toxic, and are known to have poisoned cattle.
  • All Coral trees produce a curare-like, paralysing poison, which is not fatal if ingested, as the body expels it naturally before it can be stored in sufficient quantities, and this is used medicinally in treating nervous disorders and as a muscle relaxant.
  • The bark is used externally to treat sores, wounds, abscesses and arthritis, while infusions are said to bring relief from toothache.
  • Concoctions of the leaves are used as eardrops for earache, and decoctions of the roots are used against muscle sprains.

Practical

  • The wood is whitish or greyish blue, very soft, light, with a spongy texture.
  • Trunks are often hollowed out to serve as dugout canoes and troughs.
  • Small pieces of wood are often used as fishing net floats.
  • Living kraals are often made from large truncheons, and when tarred, good quality roofing shingles or fence posts can also be made.
  • During times of scarcity, when pasture grasses are scarce and of low nutritive value, the stems makes a good protein supplement.
  • The seeds are used to make necklaces and are known as lucky beans.
  • Specimens have been planted on the graves of many Zulu chiefs, and many African tribes will not burn the wood for fear of attracting lightning.

Warnings

  • The trees are susceptible to attacks from parasites – borers can severely damage the wood, and caterpillars devour the leaves.
  • The seeds are poisonous.

Wildlife

  • The striking scarlet color of the flowers, in combination with the reward of nectar, are the main attractors for pollinators (mainly birds and insects), as the flowers do not emit any fragrance.
  • The flowers contain copious amounts of nectar, (approximately 10 drops each), and attract nectar-feeding birds such as sun- and sugarbirds.
  • The red seeds are also an important food source for many seed-eating birds, and insectivorous bird species will be lured by the vast array of insect life.
  • The range of birds that visit these trees for a meal of either nectar, seeds or insects is staggering.
  • Monkeys and baboons have been known to occasionally eat the flowers.
  • The seeds are also food for developing larvae of many winged beetle species.
  • The wood of these trees is typically soft and brittle, and when dry (a dead branch remaining on the tree), makes a wonderful nesting spot for hole-nesting birds such as Barbets and woodpeckers.
  • Secondary hole nesters such as certain Sparrows, Starlings and Hoopoes will also be attracted, while the hollow trunks are often inhabited by swarms of bees.
  • Butterflies, moths, wasps, honey and Carpenter bees are also frequent visitors of the flowers.

Advantages

  • These trees are not just decorative, but play an important role in the ecosystem, providing food and shelter for a variety of birds, animals and insects.
  • It has something to offer the gardener in nearly every season – in winter the bright flowers form an amazing contrast to the bare, grey branches, adding warmth and colour to an otherwise bare winter garden, and during the summer months they provide lovely, light filtered shade that creates an ideal condition for growing smaller, more sensitive herbs and shrubs.
  • The trees can be used in soil conservation and erosion control, and also have nitrogen fixing abilities (bacteria on the roots can actively convert atmospheric nitrogen, essential for plant growth), thus they will improve the quality of the soil for all plants in the vicinity.
  • The thorny branches make the trees suited for security, boundary or privacy screens or borders, and the trees are often used as live fences around homes, water sources and crops.
  • They are fast-growing, water-wise, require minimal upkeep, and can reach substantial sizes in a short space of time.
  • Large rock gardens are the perfect background for these trees, as well as street sides, large parks, reserves and farms.
  • As a single specimen on a large, open lawn, these trees are sure to attract attention.

Tolerance

  • A coastal species that may not survive very cold inland weather, these trees suffer damage from biting cold very easily.
  • If adequately sheltered when young (first 3-4 years), and planted in a protected position, they might withstand some frost, but flowering will be severely hampered.
  • It can tolerate relatively moist soils but will also endure a fair amount of drought.
  • The branches are quite brittle and soft, and the trees should be planted in a wind-sheltered position to prevent breakage.
  • They can grow in relatively poor-quality soils.

Growth Rate

  • Average to fast – under ideal conditions, a rate of 700-1000 mm per year.

Lighting

  • Full sun.

Soil & Water

  • The trees will accept a wide range of soil types, from sandy to slightly clay or loamy, with a neutral to alkaline pH.
  • Optimal development occurs in a very well-drained, humus rich soil.
  • The Coastal Coral Tree responds well to occasional, deep watering, as the heavy branches of soft wood are prone to breakage, so it is best to water infrequently, but generously.
  • During very hot and dry periods, extra water should be given. These trees naturally thrive in areas with a mean annual rainfall of 800-1500 mm.

Propagation

  • Freshly collected seeds should be sundried for 1 day, after all residue has been removed, those damaged by insects and disease should be discarded.
  • Store them in airtight containers, in a cool, dry place.
  • They can be stored for several years, retaining a high percentage of viability.
  • It is recommended that a test be done first to ascertain which seeds are viable – soak the seeds in water overnight and select only those that have sunk to the bottom.
  • The water also helps to soften the hard seed coat so that germination takes place more easily.
  • Sow the seeds in late spring or early summer, in a well-drained medium of two parts fine river sand and one-part compost.
  • Place the seeds about 2-3 cm apart and cover with an additional thin layer of sand.
  • Store in a well-ventilated, sheltered area away from direct sunlight, and mist daily.
  • The medium can be drenched with a long-acting pre-emergence fungicide to prevent seed decay and seed-borne diseases, such as damping off, root rot and downy mildew, or a pre-emergence fungicide can be used on the seeds.
  • The trees can also be propagated by means of giant hardwood cuttings (30-40 cm in length), taken just before the trees come out of dormancy in late winter or very early spring.
  • After taking the cutting, allow the wound to dry for 1-2 days, then bury one-third of the cutting in soil (similar to seedling mixture), while leaving two-thirds exposed.
  • A rooting hormone can be used but is not essential.