Coprosma robusta, commonly known as karamū, is a flowering plant in the family Rubiaceae that is endemic to New Zealand.

[2] Domatia (small holes on the back of the leaf at the intersection of veins) and stipules are significant characteristic features of Coprosmas.

[3] Karamū stipules are black, hairless and obtuse with slightly serrated margin that are united at the base [2] The glossy leaves of karamū range from 5 to 12 centimeters (2.0 to 4.7 inches) long, with elliptic-oblong shape and acute or obtuse leaf apex and with obvious veins.

[1] Flowers are small and white, axillary, dense, have four lobes and have a different appearance in male and females.

[4] 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.

Karamū can also be found in the urban environment of many Christchurch city green spaces (e.g. park like Riccarton Bush).

It can also grow in a large range of altitude varying from 0 to 1,200 meters (0 to 3,937 feet) under full sun to shady, windy and frosty circumstances.

[10] Karamū is an extremely hardy plant that can grow in a large range of environmental conditions from full sun to shady, from dry to moist, and can tolerate frost and wind.

[13] Herbivorous mammals such as goats (Capra hircus) and deer (Cervus elaphus) have a severe impact on karamū, and hares (Lepus timidus) and rabbits (Oryctolagus cuniculus) eat the seedlings.

Experiments with karamū shows its growth is assisted by the presence of mychorrhizal fungi assuming there is sufficient phosphorus in the soil.

The leaves are believed by Māori to have the ability to deal with kidney troubles and bark can be and used to treat stomachache and vomiting.

[17] Baptists used the leaves in a ceremony and green karamū branches will be held by tohunga in tohi for newly born babies.

[17] Karamū is noted for its quick bushy growth and for this reason is commonly cultivated and frequently used for revegetation projects.

This differential survival of the sexes in long-lived species is usually attributed to differences in reproductive effort between male and female plants.