Biennial or perennial megaherb < 5 m tall. Taproot is fibrous. Stems are hollow, finely haired and covered in red/purple spots. Leaves are compound, large, < 50 cm across and serrated. Flowers are small, green/white and borne in umbels.
To help protect our environment:
Riparian and forest margins, roadsides, flood plains, drains.
Seeds dispersed by water, gravity and wind. Human-mediated dispersal through movement of contaminated soil and deliberate plantings.
Forms dense infestations, suppressing native vegetation and exposing banks to erosion during periods of seasonal dieback. Can cause photodermatitis in humans, possibly requiring medical treatment.
Do not attempt to undertake control of this species. Please report to Auckland Council.
CAUTION: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.