Karamu

(Coprosma robusta)

What is Karamu?

Karamu is an evergreen shrub or tree native to New Zealand. Originally introduced as a garden ornamental karamu is now an environmental weed.
Karamu is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of karamu are prohibited in Tasmania.

How to identify karamu

Karamu grows to around 6 metres. The leaves are opposite, large, thick and glossy, and with pointed tips. Karamu flowers are small, greenish and growing in clusters. The fruit is a fleshy berry, green initially before maturing to orange-red over late summer.

Karamu is similar to the related mirror bush (Coprosma repens) however mirror bush has thicker, very glossy leaves that are rounded with a blunt tip.

Image top: Karamu branches with fruit, © Karen Stewart

Image above: Karamu leaves, © Karen Stewart

Karamu in Tasmania

Karamu is recorded from the east coast, Fern Tree, the Gordon River Dam and larger populations are found along the Derwent River around New Norfolk.
Karamu is able to invade relatively undisturbed native vegetation, particularly damp and wet eucalypt forest. It forms dense thickets and can eventually shade out native understorey species.

What is the legal status of karamu in your area?

The legal responsibilities of landholders and other stakeholders in dealing with karamu are laid out in the Statutory Management Plan for Karamu.
Use Table 1 (Zone A municipalities) in the Statutory Management Plan for Karamu to find out whether this weed occurs in your municipality.

What you need to do

If you locate karamu anywhere in Tasmania, or if you find a plant that you think could be karamu, immediately contact Biosecurity Tasmania on 03 6165 3777 to report this weed.

Detailed management and control guidelines for karamu can be found in the Karamu Control Guide. Refer also to Herbicides for Karamu Control. For further information see DPIPWE's Weed Links and Resources.

See also
Herbicides for Karamu Control
Statutory Management Plan for Karamu
Weed Links and Resources

Other useful links
Pest Genie
APVMA

Karamu Control Guide

Spread of karamu

Karamu reproduces by seed, with male and female flowers occurring on separate plants. Seed is dispersed mainly by birds, as well as in dumped garden waste.
The seed appears to be short lived so that a seed bank does not develop in the soil.

Physical removal

Seedlings and smaller bushes can be hand-pulled or dug out. The entire root system should be removed, as plants may re-grow from root-stock left in the ground.
The tops are likely to break off when pulling, so if roots remain in the soil they should be dug out.
Removed material bearing fruit should be destroyed (burning or bagging) and not dumped.

Burning

Burning will kill the top growth, but even quite small plants can re-grow from the rootstock.

Chemical control

Under an off-label permit issued by the Australian Pesticides and Veterinary Medicines Authority (APVMA), a number of herbicides can be used to control karamu in Tasmania. See Herbicides for Karamu Control for more information.
Herbicides are most effective on smaller plants under 2 metres and on fresh regrowth.
The cut-paint method provides best control, with seedlings, smaller plants and any regrowth removed manually.
Follow-up herbicide treatment may be required as plants can reshoot.

Herbicides for Karamu Control

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