Conkerberry

Appearance

It grows as a multi-stemmed shrub, 0.5 to 3 metres in height. The leaves are glossy green, opposite, narrow ovate to lanceolate and 1–5 cm in length. The branches bear thorns of 1–3 cm length. White, star-shaped flowers ~1 cm across are followed by ovate green berries, 1–2 cm in length, which turn black or dark purple when ripe.

Naming

It is most well known in Australia, where it is also called "currant bush" or, more ambiguously, "native currant" or even "black currant". It is, however, neither closely related to plums nor to true currants, which belong to entirely different lineages of eudicots. In India, it is also called wild karanda /wild karavanda, referring to the related karanda. "Carissa spinarum" is often discussed under its many obsolete synonyms.

Habitat

"Carissa spinarum" is most often found in semiarid coastal regions on fine-textured soils such as clays and clay-loams; in more arid regions the plant tends to be confined to areas of higher moisture such as at the base of hills or floodout areas. But it has a high ecological tolerance and can live in a wide range of habitats. In Australia for example, it is often found in association with "Eucalyptus brownii", poplar box, gidgee or brigalow, in coastal rainforest, gallery forest and vine thickets in regions receiving in excess of 900 mm annual rainfall, as well as softwood scrubs and open eucalypt savannas receiving less than 700 mm annual rainfall.

Conkerberries are edible, but only when fully ripe; they have a sweet flavour, but the milky sap of this plant – and its unripe fruit – is poisonous, as typical for the Apocynaceae. They are a popular bush tucker food for Australian Aborigines in Central Australia. The fruit is known as "merne arrankweye" in the Arrernte language, "anwekety" in Anmatyerr and "nganango" in Pintupi. The fruits are also a popular food for the Australian bustard, emu and many other birds in its range. Its leaves provide food for butterflies and moths

"Carissa spinarum" is frequently a weed in grazing land in northern Australia, choking out grasses, reducing the ability of livestock to feed, interfering with stock handling and providing a refuge for vermin. The plant is capable of reproducing rapidly by layering and is difficult to control mechanically and expensive to manage with herbicides. On the other hand, it has been used in attempts to restore small-bird habitat in disturbed dry rainforest in Queensland, Australia.

Parts of the plant are used medicinally for joint and muscle pain by the Maasai people of Kenya.