Koster's Curse is a densely-branched perennial
shrub up to 5 m tall but normally between 0.5 and 3 m. In windy areas,
it is scrambling and is less than 1 m tall. The oppositely arranged
leaves are up to 15 cm long and 8 cm wide. They have prominent veins
and are dark green. Most plant parts, including stems, leaves and
calyx, are hairy. The flowers, 0.5-1 cm across, have white or pink
petals and are borne on short flower-stalks in cymes of 6-20 flowers in
leaf-axils or at branch-ends. The berries are borne in clusters and
turn from green to blue-black or deep purple as they mature.
"Koster's curse" is a commonly used name in places where the plant
grows as a noxious weed, such as Hawaii. Koster was the man who between
1880 and 1886 accidentally introduced seeds of C. hirta to Fiji in
coffee nursery stock, where its problematic nature was first noticed
around 1920. It is a native of South America, naturalised in
Paleotropics.