Coprosma robusta, commonly known as karamu, is a flowering plant in the family Rubiaceae. It can survive in many climates, but is most commonly found in coastal areas, lowland forests, or shrublands.
Karamu can grow to be around 6 meters tall, and grow leaves up to 12 centimeters long. Karamu is used for a variety of purposes in human culture. The fruit that karamu produces can be eaten, and the shoots of karamu are sometimes used for medical purposes.
Karamu is endemic to New Zealand. However, it is gradually becoming naturalized in areas of the south-east coast of Australia such as Victoria and Tasmania and has been rated as a weed threat there.
New Zealand range:
It is widely distributed across New Zealand in both the North and South Islands. On the Chatham Islands between Waitangi and Owenga, there is a small area where karamu has become naturalized. They can often be observed naturally in lowland forest. Judging from the distribution map on New Zealand Plant Observation, the distribution of karamu increases with the differentiation in lower altitude which means more karamu in the North Island.
In Canterbury, karamu is found on Banks Peninsula in fragments of regenerating native bush and bush remnants. Additionally it is also found in forest margins and edges of the montane and lowland forests in the southern alps at the start of the Canterbury planes. Karamu can also be found in the urban environment of many Christchurch city green spaces (e.g. park like Riccarton Bush).
Karamu can be widely found near coastal, lowland and lower montane areas. It can also grow within shrub lands and expansive areas within dense trees such as lowland forest. However, the population decreases in lowland forest such as beech and kahikatea forests. Normally karamu is a hardy plant that can adapt to infertile soils, poorly drained and exposed lands. It can also grow in a large range of altitude varying from 0–1200 meters under full sun to shady, windy and frosty circumstances.
Settlers in the late 19th century, sensing the relationship of coprosma to the coffee plant, did try roasting and grinding the seed of karamu and taupata. Notes from a meeting of the Wellington Philosophical Society describe that “the beans …… when roasted and ground have a splendid coffee aroma and when made into coffee the result seems to be thoroughly satisfactory.” Coprosma and Coffea (the coffee plant) both belong in Rubiaceae, the madder family.