Handsome large shrub for shade

Posted by on May 4, 2016

Have you ever wondered about the large, glossy green shrubs growing adjacent to the Game Parking Garage in Rawson Street? Last summer and early autumn they were dressed in trusses of beautiful white flowers, contrasting against the shiny glossy leaves. They seem to florish in their allotted space, rewarding pedestrians and passersby with their faint perfume.

duvornoia

Duvernoia adhatodoides

Acanthaceae

Pistol Bush, Pistoolbossie

 

duvernoiaadhatodoides_shadeDuvernoia adhatodoides is a fast growing evergreen shrub up to 3 m tall, or a small tree, 7–10 m in height. It can be single or multi-stemmed, and has a dense crown of dark green leaves. The bark is dark brown, rough and fissured. The branches are brittle. The leaves are large, oval- to lance-shaped and tapering to a point, up to 230 mm long and 150 mm wide, shiny dark green, with wavy margins. The fragrant white flowers are showy and orchid like with  beautiful purple markings.This shrub flowers young and the flowering period can last up to three months. The fruits are club shaped, mature in winter and split open with an explosive crack, scattering the seeds in all directions –  hence the name pistol bush.

The flowers are pollinated by large black and yellow carpenter bees. Mrs M.E.Barber, a well-known naturalist who lived in the Eastern Cape over a hundred years ago, wrote an article in Journal of the Linnean Society in 1871 describing how the bee alights on the lower lip and forces open the corolla tube with its proboscis to gorge on nectar. In doing so the bee’s thorax gets dusted with pollen. It then flies on to another flower where its thorax brushes against the protruding stigma, depositing pollen to ensure fertilization, before picking up a more pollen. The fruits are club-shaped capsules, about 3 x 1 cm, dehiscing explosively with a loud crack (hence the common name).

Distribution and Habitat

Northern part of the Eastern Cape to KwaZulu-Natal and Mpumalanga, under forest canopy, on forest margins and on rocky outcrops

Planting Suggestions

Needs some shade, a sheltered position, well composted soil, rich feeding and plenty of water. Mulch to retain water. Water regularly for best results. Propagates easily from seeds or cuttings. This species does best in a cool, moist site and is well-suited to coastal gardens, although it is best not exposed to strong, drying winds.

It can be used as a background planting for the herbaceous border, in the shrubbery, as a screening plant or an informal hedge. Plant it in sun, semi-shade or light shade, in fertile, well-composted soil and water well, particularly during its spring-summer growing season. It is sensitive to frost, but can be grown in cold areas where frost is not too severe, as long as it is protected. Plants growing in semi-shade, tend to have more lush and deeper green foliage, but those in a more sunny position, flower better. Prune to shape or to maintain as a shrub.Duvernoia_adhatodoides

Derivation

The derivation of the genus name Duvernoia is not explained, but is possibly named after J.G. Duvernoy, a German botanist and student of Tournefort, who wrote a Flora of Tübingen in 1722. The species name adhatodoides means ‘resembling Adhatoda’ another genus in the Acanthaceae, containing many species of perennial herbs found in the Old World tropics, but only two in southern Africa.

Info: SANBI

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