Jacarandas are in full bloom in Pretoria, heralding the beginning of summer, but did you know that this tree is considered to be an invasive species from Argentina in some parts of South Africa? Our own, indigenous Tree wisteria is a lovely replacement for the Jacaranda and displays similar purple blossoms from August to January.
Bolusanthus speciosus is an upright, slender, small to medium sized tree that grows to a height of between 5 and 7 m with a spread of 5 to 6 m. The rounded crown has graceful, drooping branches and the leaves are alternate, compound with up to 7 leaflet pairs with a terminate leaflet. Leaflets are shiny green above and duller below. Although deciduous, the tree is only without leaves for a short time in early spring. The dark, tawny fissured bark of the tree offsets the light green leaves and bright flowers beautifully.
Cluster of pea-like mauve flowers are borne in loose, terminal sprays up to 30 cm long during spring and early summer. The violet-blue flowers are fragrant, attracting birds and butterflies. The Tree wisteria is normally multi-stemmed, but can be pruned into a single stem.
This versatile tree is very drought hardy and frost resistant and naturalises easily in Highveld grassland areas. Care should be taken when young as it does need light protection from frost until it becomes bigger. The tree has a non-invasive root system, making it suitable for smaller gardens and it can be planted as an avenue tree. It is a protected species in South Africa, which means that no wild specimens may be cut down or damaged.