Chinese Knotweed
Polygonaceae - Persicaria chinensis

What does it look like?

Chinese knotweed can grow as a scrambling vine or as a shrub. It can grow to varying heights, depending on what it is climbing over. If it as growing as a shrub, without support, it can reach heights of up to 1m. The leaves are 4-16cm long, soft and wavy-edged with a white blotch in the shape of a "V". It has pinkish stems and cream/pink flowers.

Why is it a problem?

Chinese knotweed can tolerate a wide range of environmental conditions, including shade, high and low temperatures, high salinity and drought. In its native range it grows in wet valleys, grassy slopes, mixed forests, valleys, and mountain slopes from sea level to 3000 m. Outside its native range, it can be found in disturbed sites, home gardens, abandoned gardens, riverbanks, roadsides and in agricultural lands. In New Zealand it has the potential to affect forestry, orchard and nursery operations and become a nuisance plant in home gardens and life style blocks. Chinese knotweed is a highly invasive plant that quickly smothers other plants and trees.  It can seriously impact on forest floor habitats especially on forest fringes and in light wells. Plants grow from rhizomes (roots) and stem fragments. It is not known if the plant can produce seeds in New Zealand. Plant fragments can be spread in garden rubbish and soil and on contaminated gardening tools, including lawnmowers. It may also be spread intentionally, for medicinal uses.

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