Pirri-pirri-bur Acaena novae-zelandiae

Status Amber - Vulnerable and Near-Threatened
Best Time to See

A non-native invasive plant.

Originating from Australia and New Zealand, this short, creeping plant is readily available from garden centres and is popular in rock gardens. It forms dense mats of lobed leaves and ball-like heads of hooked seeds (burs).

Originally introduced to the country via seeds in imported wool, the pirri-pirri bur now mainly spreads in the wild through the dumping of garden material, but also through seed and stolen fragments. It has been found on sand dunes, cliffs, heaths, conifer plantations, old gravel workings, roadsides and disused railways.


Wet slopes, rough pastures, dunes, grassy areas and woods.

What's the problem?

Pirri-pirri bur becomes especially invasive when it establishes on cool, damp cliffs and upland habitats – often the very types of site where threatened native plants occur. Its hooked burs mean it is easily spread in the wild by sheep and other animals. It has also proved a problem in dune habitats, such as those on the island of Lindisfarne.

Rapid Risk Assessment

***** Critical Risk

Plantlife's position

Plantlife believes this species should be listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales.