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.

Description

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

Stems are pinkish in colour and leaves are generally soft textured, serrated edged and 4-16cm long.

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 used in herbal medicines.

Chinese Knotweed
Chinese Knotweed, Bushes

Impacts

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.

It 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.

It is thought this plant will be easily spread as plant cuttings or roots. It can be moved 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. Do not attempt to control this weed yourself.

Page last updated: 25 September 2013