(=Acacia robusta robusta)

A small to medium upright deciduous tree with a crown that is typically a lot narrower than it is tall. Its narrow upright growth and majestic stature make Vachellia robust robusta a popular thorn tree for smaller gardens.

Vachellia robust robusta's narrow. upright growth and majestic stature make it an ideal thorn tree for smaller gardens.

Vachellia robusta robusta‘s narrow. upright growth and majestic stature make it an ideal thorn tree for smaller gardens.

 

Family:                       MIMOSACEAE    (Thorn-tree family)

Name Derivation:

  •  Vachellia– after George Harvey Vachell (1789 – 1839), chaplain to the British East India Company in Macao (1825 – 1836) , who collected plants in China.
  • robusta – robust.

Common Names:           Broadpod Robust Thorn (Eng), enkeldoring (Afr), mooka (Nso), mvumbangwenya (Tso), mokhu (Tsw) muvumba-ngwena (Ven), and umngamanzi (Zul)

SAF Number:                  183                         Z Number:            202

Form

  • A small to medium tree with an upright but slightly flattened crown.
  • Has a very robust appearance.

Size:                                   4 – 6 m by 3 – 5m, may reach 10 m

Flowers:

  • Round balls.
  • In clusters at the ends of branchlets.
  • Free flowering and quite spectacular in full flower.

Flower Colour             Cream to butter-yellow.

Flowering Months:      Aug – Oct.

Fragrance:                      Flowers are sweetly scented.

The cream to butter-yellow flowers of Vachellia robusta robusta are held in dense round balls.

The cream to butter-yellow flowers of Vachellia robusta robusta are held in dense round balls.

Foliage:

  • Deciduous.
  • Leaves are bipinnate, larger and more rounded than Vachellia karroo.
  • Borne on woody cusions.
  • Leaves are dark green.
The dark green, bipinnate, leaves of Vachellia robusta robusta are larger and more rounded than the similar Vachellia karroo.

The dark green, bipinnate, leaves of Vachellia robusta robusta are larger and more rounded than the similar Vachellia karroo.

Thorns:

  • Long (4-6 but up to 10 cm) straight white thorns in pairs.
  • Larger thorns may be furrowed along the top surface.
  • Older branches have fewer and less developed spines.
The straight, paired thorns of Vachellia robusta robusta are arranged alternately along the branches.

The straight, paired thorns of Vachellia robusta robusta are arranged alternately along the branches.

Fruit:

  • Pods are leathery or woody, fairly straight or thickly sickle shaped.
  • There is no constriction between seeds.
  • Pods remain on the tree for quite a long time.

The pods of Vachellia robusta robusta are woody, thick and broad.

Bark:

  • Bark is dark brown, rough and fissured.

 

In the Garden:

  • Well suited to medium and larger gardens and large pavements as feature trees.
  • Because it is both drought and cold resistant, it can be grown in areas where these factors limit choice of trees.
  • A very good choice for larger wildlife friendly gardens, attracting insects, butterflies and birds.
  • Should make good bonsai subjects.

 

Soil Needs:

  • Grows naturally in many different soil types, added nutrition will reward the gardener.

Planting spacing:

  • Plant as a specimen trees
  • May also be planted in  groves 3 m or more apart.
  • Plant 2 m apart to form a security hedge

 Care:

  • A low maintenance garden tree.
  • Plant in a cubic metre hole with lots of compost and some bonemeal can produce a 1 m and more growth in a season.
  • May be pruned to shape.

Cold Hardiness:              Very cold hardy.

Water Requirements:   Drought  hardy.    

Light Requirements:     Full sun.

Roots:                                 Aggressive roots, do not plant too near paving, swimming pools, walls or buildings..

Birds:

  • Used by insectivorous birds for foraging and gleaning.
  • Flowers are eaten by Grey go-away birds and probably other birds as well.
  • The thorny branches are used as nesting sites.

Butterflies:

  • In Gauteng a possible larval host to Thorn-tree blue, Velvet-spotted blue, Topaz-spotted blue, Black heart, Mashuna hairtail, Talbot’s hairtail, Black-striped hairtail and Black-tipped scarlet
  • Elsewhere possibly larval host to Mirza blue, Natal spotted blue, Little hairtail, Otacilia hairtail, Dark-banded scarlet, Purple gem and Brilliant Gem.
  • Adult butterflies feed from the flowers

Bees:                                    Flowers provide nectar and pollen to bees and other insects.                          

Medicinal:                         No reference to medicinal uses.

Poisonous:                        Not poisonous.

Notes of interest:

  • Flowers, pods and leaves eaten by stock and game.

 Natural Distribution:

  • EC, KZN, northern M, G, L, NW, northern NC, eastern Bot, south-west and central Zim.
  • Vachellia robusta robusta is endemic to southern Africa.

Natural Habitat:              Grasslands, savanna-bushveld, and savanna-lowveld.

Vachellia robusta robusta in grassland habitat in Nooitgedacht, Gauteng.

Vachellia robusta robusta in grassland habitat in Nooitgedacht, Gauteng.

 

 

 

 

 

© Malcolm Dee Hepplewhite & Witkoppen Wildflower Nursery, (Text and Photographs) 2017.