Chinese knotweed

Chinese knotweed is a perennial vine that is scrambling, and mat-forming. It can grow as a one metre tall shrubby plant or a climbing vine <10 metres if supported by other plants.

Description

• Leaves are 16x8cm, yellow-green, usually oval shaped with wavy edges and a reddish middle vein. They can be smooth or covered in stiff hairs.

• Stems are red with stripes or streaks, woody at the base, and branched.

• Flowers are pink/pale pink, tubular or cup shaped, in clusters of 1-3.

• Fruits are 3-sided, black, and fleshy.

• Seeds are dispersed by birds. Vegetative spread from stem and rhizome fragments.

• Habitats include forests, riparian margins, grasslands, disturbed sites, crops, roadsides, and urban areas.

What you need to know

Chinese knotweed forms dense mats, smothering native vegetation and preventing seedlings from establishing.

Management approach

Chinese knotweed is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.

Control

Do not attempt to undertake control of Chinese knotweed yourself. Report any sightings to us.