Coprosma robusta aka Karamu

Coprosma robusta, known as karamu, belongs to the Rubiaceae family. It is native to New Zealand and the Chatham Islands. Its range includes both North Island and South Island. It grows in lowland woods and areas of scrub. It often occurs on soils laid down by rivers. Records place its southern limit near 45 degrees south. Kew describes its climate as subtropical and its form as shrub or tree.

This evergreen shrub reaches about 16 feet [5 metres] tall. It keeps its leaves throughout the year. That lasting cover suits woodland edges and sheltered garden sites. Plants tolerate hard pruning and close clipping. Gardeners can therefore shape them where space or design calls for control. Some named forms have been selected for their garden value. The species can cross freely with other members of its genus.

Male and female flowers usually grow on separate plants. Wind carries the pollen between them. Grow both sexes together when seeds or fruit are wanted. Plants cannot normally fertilise themselves. Some may produce a few flowers of the other sex. The orange fruit measures about 0.35 inches long and 0.2 inches wide. Plants can bear fruit in large amounts. The flesh tastes sweet, though its flavour is mild. People eat the fruit raw or cooked. Roasted seeds also serve as a coffee substitute, though each seed is small.

Choose moist soil that drains very well. Neutral or slightly acid soil suits this plant. Sandy and loamy soils work, and reports note broader soil tolerance. It grows in full sun or light shade. A woodland edge or sheltered wall offers possible garden sites. Frost tolerance needs care: reports differ on its hardiness in Britain. One limits outdoor growth to the mildest districts. Another records fair hardiness in Essex. PFAF lists USDA zones 8–11. Protect young plants during their first winter outside.

Seed and autumn cuttings offer ways to raise new plants. Seed can take more than a year to sprout. The wood yields a yellow dye without a fixing agent. Traditional uses include leaf preparations for kidney complaints. Boiled leaves and twigs have also served as wound treatments. These records describe past uses, not proof of medical benefit. PFAF reports no known hazards, but this does not establish safety for every use.