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GENERAL
Origin
:
sub-tropical,
tropical
Vigour
:
fast growing
Humidity
:
very arid
Propagation :
sowing and
pricking out
Maintenance :
low
CONDITIONS
Urban climate :
resistant
Dessication :
resistant
Stagnant water :
vulnerable
Irrigation
:
low
Salinity/ppm :
moderate (2000
ppm)
Hardiness
:
0°C
SHAPE
Type
:
tree, shrub
Height
:
4 m-15 m
Spread
:
6 m-15 m
Foliage
:
semi-evergreen
FLOWER
Colour
:
bright yellow
Size
:
1 cm - 2 cm
Period
:
April - May
Smell
:
pleasantly
scented, flower
FRUIT
Type of fruit :
pod
Fruit size
:
4 cm - 10 cm
Endemic to southern Africa, A. karroo has been selected from the exotic acacias as having
potential for planting in Arriyadh. Typically a shrub, it will grow into a medium-sized tree under
good conditions and grows rapidly with regular water. Variable in shape and size, it has a rounded
crown, branching from the lower part of the trunk. The bark has deep fissures and is red on
young branches. Fragrant, yellow flowers, opening in clustered heads in late spring. Narrow seed
pods are flat, straight or curved. A. karroo is a pioneer tree with an ability to fix nitrogen, but it
is relatively short-lived (up to 40 years). The tree is deciduous in cold areas and prone to frost
damage. It has a long taproot, but its roots are invasive; planting near paving/foundations should
be avoided. Propagation is by seed soaked in hot water and left overnight; young trees are best
fertilised with compost and bonemeal. A. karroo grows in most free-draining soil types, in full
sun or partial shade. Drought-tolerant, the root zone should be deep-watered every one to two
months during the summer. A beautiful patio-sized tree for the garden, its bright yellow flowers
against dark green foliage and reddish-brown bark are highly attractive. Useful for erosion control,
as a windbreak, thorny informal hedge, or barrier. Maintenance includes careful training of the
leader, gradual removal of side branches until all are above head height, so that the long thorns
are no problem, and also spring pruning of dead wood. The tree is prone to attack by mealybugs.
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Acacia karroo,
Mimosaceae
Sweet Thorn