Chinese knotweed

Persicaria chinensis

Chinese knotweed

Chinese knotweed

Legal Status: Unwanted Organism - MPI
Status in New Zealand: Controlled
Organism: Land plants

Other common names: liane rouge, red bush or huo tan mu.


Chinese Knotweed
Chinese Knotweed. Leaves have a distinct v-shaped blotch.

Chinese knotweed is a perennial herbaceous vine that quickly spreads and covers any available surfaces. When not climbing over other plants or structures, plants grow from 70cm to 1m tall.

Stems are pinkish in colour and leaves are generally soft textured, serrated edged and 4-16cm long. The leaves have a conspicuous pale v-shaped blotch.

Chinese knotweed flowers in autumn. Flowers are cream/pink and grow in clusters at the end of leafed stems.

Plants grow from rhizomes (or tubers) and stem fragments. Rhizomes are irregular in shape and generally 6-15cm long and 4-12cm in diameter. The tubers are reddish brown in colour.

Dried rhizomes are often used in herbal medicines.


Chinese knotweed flowers
Chinese Knotweed – flower detail

Chinese knotweed is a highly invasive plant that quickly smothers available surfaces, including other plants and trees.

It could overrun native plants and forests, particularly along forest fringes. It has the potential to affect forestry, orchard and nursery operations and could become a nuisance plant in home gardens and lifestyle properties.

Chinese knotweed can tolerate a wide range of environmental conditions, including shade, high temperatures, high salinity and drought. It is suited to growth in many regions in New Zealand, especially North Island regions.

This plant can be easily spread – for example, with garden rubbish and on contaminated gardening tools, including lawnmowers. At present, it is not known if the plant can fruit in New Zealand conditions.

What to do if you find this plant

Contact MPI's 24-hour pest and disease hotline – 0800 80 99 66 or seek advice from your regional council. As eradication is difficult and requires multiple treatments, do not attempt to control this weed yourself.

Page last updated: 13 June 2016