Wednesday, August 5, 2009

Acacia galpinii – Monkey thorn

The Acacia galpinii is the largest of the South African Acacia species. The common name, Monkey thorn, is thought to refer to the tendency of monkeys to seek refuge in these thorny trees and their fondness of feeding on the pods. The Tswana name “Mongangatau” means “the one that catches like a lion” and is attributed to the thorns that tend to catch on clothing and skin. In its natural habitat, the Acacia galpinii is preferred by large animals such as Giraffe, Kudu and Elephant to provide shelter from the sun.


Botanical Name: Acacia galpinii
Common Name: Monkey thorn
Genus: Fabaceae
RSA National Tree No’: 166


This tall handsome tree with its luxuriant foliage and wide spreading branches makes a fine specimen in large gardens and parks. Planted on a lawn, it provides dappled shade in the heat of summer. The clusters of creamy yellow, honey scented flowers create a spectacular sight and attract insects, wasps and bees to the garden, whilst many bird species prefer nesting in the Monkey thorn as it offers protection from a variety of predators. When planted as an avenue along our roadsides this fine, hardy tree looks quite stunning and for those areas where a security hedge is required the Acaia galpinii provides an impenetrable barrier if kept trimmed down. Do not plant this tree too close to buildings as it has an extensive root system.


Height: 25 – 30m
Spread: 8 – 10m
Deciduous/Evergreen: Deciduous
Growth Habit: Acacia galpinii occurs in open wooded grassland and along rivers and streams.
Bark: The bark is pale, flaking and creamy yellow when young, becoming brown, rough, corky and longitudinally furrowed when mature.
Foliage: The leaves of the Monkey thorn are 5.5 – 11cm long with 9 – 14 pairs of pinnae which curve down from the rachis, each bearing 13 – 40 pairs of leaflets. There are short hooked thorns at the base of the leaves. Interestingly, the leaves fold at night.
Flowers: The creamy yellow, honey scented flowers resemble bottlebrushes and are borne in clusters from October to January.
Fruit: The reddish to purple – brown pods are up to 28cm long and 3,5cm wide, ripening between February and March.
Seed: There are approximately 8 – 15 seeds per pod which are released when the pods fall to the ground.


Growing regions: The Acacia galpinii is found in Zimbabwe, Eastern Botswana and in the North West Province and Northern Province of South Africa.
Growing conditions: The Monkey thorn prefers a sunny position. Plant in a large hole to which a generous amount of compost has been added and water regularly in the first year.
Best season: Spring - Summer
Hardiness: This hardy tree can withstand hot, dry conditions and a fair amount of frost.
Propagation: To propagate, soak seed in hot water for about six hours before planting into a seedling tray with ordinary river sand.
Growth rate: Fairly fast – about 1m per year.


The Acacia galpinii is widely recognised as an indicator of sweet veld, which retains its nutritional value through winter. The wood, which is heavy and coarse grained, was used for building wagons and although the wood is difficult to work, it was often used for making good sturdy furniture. When grown from seed, the Monkey thorn is a popular subject with Bonsai enthusiasts as it can be easily trained into a variety of interesting shapes.

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