Acacia karoo

Accession Count: 1
Common Name: Karoo Thorn
Family Name: Fabaceae
Botanical Name: Acacia karoo
Synonyms:
Family Synonyms: Leguminosae
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics: Acacia karoo is a small, deciduous tree or shrub with bipinnate leaves resembling those of a mesquite. The long green leaves display up to twenty sets of pinnae, with the leaflets measuring to one-half inch long (2). Flowers are golden-yellow pompoms typical of many acacias, held in clusters of four to six, and are sweetly scented. The thorns, which are a striking feature of A. karoo, are modified stipules that can reach up to three inches long. They are held in pairs at nearly right angles to the branch. This species is known to reseed fairly easily (2).
Compound: Aca kar
Geographic Origin: South Africa
Ecozone Origin: Afrotropic
Biome Origin: Savanna
Natural History: The flowers of the karoo thorn are said to attract larvae and adults of several butterfly species as well as other insects. Birds nest in the canopy, taking advantage of the long, white spines that give protection against predators.
Cultivation Notes: A. karoo typically grows in woodland and bushland habitat, and grows better in clay and loam soils, because of this it is often considered an indicator plant for locating rich soil. However, it is also able to grow in desert and coastal sand dunes as well (1). The karoo thorn typically grows as a shrub in nature, but with the correct training and pruning it becomes an attractive small tree (2). This species is relatively tough as it needs water monthly to none at all, is able to survive temperatures as low as 18° F and is suitable to grow in both full sun and partial shade.
Ethnobotany: Traditional uses of Acacia karoo in the southern part of Africa have developed over many decades, both by Indigenous people and colonizers. The red and shaggy bark can be made into rope or used for tanning leather. The wood of the karoo thorn is extremely hard, and useful for woodworking and firewood. Stock and wildlife feed on the leaves, flowers, and pods. Honey made from the nectar is mild and sweet. Medicinal uses of the karoo thorn include wound poultices, cold remedies, and more. The dried leaves are said to have antibacterial and antioxidant activity. In addition, early naturalists were known to have used the long spines to pin the exotic insects they had collected. Great for arid and transition landscapes, A. karoo is also utilized for erosion control in disturbed areas (2). When grown as a shrub, A. karoo is often used as an informal hedge, buffer, or barrier.

Height: 6 - 10 feet
Width: 6 - 10 feet
Growth Rate: Moderate Growing
Grow Season: ForeSummer
Flower Season: Spring
Color: Yellow
Function: Screen
Spread: Non-spreading
Allergen: Non-allergenic
Invasive: Benign
Toxicity: Benign
Hardy: Hardy
Water Use: Low water Use

Citations:
  1.  KEW Botanical Garden
  2. Jones, Warren D, and Charles M Sacamano. Landscape Plants for Dry Regions : More Than 600 Species from around the World. Fisher Books, 2000.
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Acacia karoo