Plant of the Week: Coprosma Robusta

By Davis Landscape Architecture @DavisLandArch

Coprosma robusta (18/11/2012, Kew Gardens, London)

Position: Full sun to partial shade

Flowering period: Early spring

Soil: Moist, well drained

Eventual Height: 4m

Eventual Spread: 2m

Hardiness: 9a – 10b

Family: Rubiaceae

Coprosma robusta is a fast growing, evergreen shrub . Its bright green, leathery leaves are elliptic with entire margins, up to 12cm long and 5cm broad. Its cream flowers are dioecious, produced in terminal clusters, wind pollinated and are not self fertile. Its orange fruit are a berry, up to 9mm long and take up to a year to ripen.

Coprosma robusta, commonly known as Karsamu, is native throughout New Zealand. In its native habitat it is found in lowland scrub, woodland margins or forests. It is a fast growing colonising shrub.

Coprosma robusta Leaf (18/11/2012, Kew Gardens, London)

The etymological root of the binomial name Coprosma is derived from the Greek Kopros meaning ‘excrement’ or ‘ordure’, alluding to the fetid smell of this shrub. Robusta is from the Latin meaning ‘strong’.

The landscape architect may find Coprosma robusta useful as a shelter shrub in revegetaion and soil stabilisation projects. It is also suitable for use as a hedging species.

Ecologically, Coprosma robusta berries are attractive to birds which aids the spread of this shrub.

Coprosma robusta Fruit (18/11/2012, Kew Gardens, London)

Coprosma robusta prefers moist, fertile, well-drained soils. It prefers an acid to neutral pH of soil. It will tolerate wet soils.

Coprosma robusta requires little maintenance. This shrub is tolerant of heavy pruning.