Article 52 19 August 2009
Dune Soap-berry Deinbollia oblongifolia
Deinbollia oblongifolia - dune soap-berry, duineseepbessie ; iQinisa-masimu
Walk through any patch of coastal bush along the coastal belt of KwaZulu-Natal and the Eastern Cape to around East London and you’ll find this medium sized shrub of about 5 metres tall. It is a common garden "pioneer/volunteer" plant that often arrives and looks in its early stages for all the world like a young forest mahogany (Trichilia dregeana). The leaves are compound and the 5-8 pairs of leaflets have a paler green slightly matt appearance hence the confusion with the forest mahogany, which in fact has a darker green compound leaf that is fractionally glossier.
The dune soap-berry is usually multi-stemmed and if it isn't then you should nip out the terminal bud to force it to become multi-stemmed thus ensuring more terminal clusters of flowers which are small and creamy coloured. It is however the pale yellow 10mm diameter fruits that make me want this plant in my garden, especially in the winter months when all else is dry and dormant this plant has ripe fruit that provides a welcome meal for the birds and monkeys. If you are feeling a little adventurous then try the fruit the fleshy inner part is quite palatable to us humans!
This plant has another use that we often overlook; the leaves are the food for the larvae of two species of butterfly of which only the former occurs in the Durban area the forest queen (Euxanthe wakefieldi). The gold-banded forester (Euphaedra neophron) is arguably South Africa's most handsome butterfly and its caterpillars feed on the dune soap-berry and the jacket-plum (Pappea capensis) however the gold-banded forester only occurs as far south as about Mtunzini. The other butterfly that uses this plant as a larval food plant is the black-and-orange playboy (Virachola dariaves) though the female lays her eggs on the fruits and the caterpillars then eat the fruits. The other butterflies that feed on this plant are the Charaxes. In this case however it is the adult flying forms that feed on the sweet fermenting fruits.
During the early summer you can also find another dune special growing on Deinbollia this is a parasitic plant Tapinanthus kraussianus - Krauss’s Mistletoe or the more descriptive common name of Lighted Matches. This parasite has flowers that are attractive to sunbirds and the fruits are relished by the fruit eating birds of the dune bush like Sombre and Yellow-bellied Greenbuls, Dark-capped Bulbul, Yellow-rumped and Red-fronted Tinkerbirds are all great distributors of this plant. When you have found a flowering plant of the Mistletoe, mark the plant and come back in two or three months to collect the fleshy fruits. Pop out the inner sticky bit that covers the seed proper, this sticky substance was rendered down in the past to make bird lime. Then stick the seed to a thin about 10mm branch or twig of a Dune Soap-berry and wait for the Mistletoe seed to germinate, about one in five seeds will attach themselves to the Deinbollia and there you are a new mistletoe in your own garden.
All in all a very useful garden subject with value as a form plant in the landscape as it is fairly columnar in shape and has distinct terminal heads of leaves. Enjoys full sun but will survive in the shade but not flower as well. I often use this plant in herbaceous or shrub borders to add a little interest and I also plant it in groups so that you get the bulking effect otherwise it can get lost amongst the other species especially while it is still small.