Invasive Species Council of Manitoba

Japanese Knotweed

Fallopia japonica

Native to Japan this shrub-like perennial was introduced as an ornamental and has also been used to stabilize soil in coastal areas. Japanese Knotweed reproduces by seeds as well as vegetatively by rhizomes. Rhizomes can grow 3 m deep and extend over 7 m away from the parent plant.

Japanese Knotweed forms dense stands that shade and crowd out other vegetation which in turn alters the wildlife habitat. The rhizomes and shoot growth can damage the foundation walls, pavement and drainage works.

This plant requires moisture so it can be seen in coastlands, riparian areas and wet grasslands. Preferring to grow in open areas but can also grow in the shade Japanese Knotweed is also tolerant of a variety of soils and a wide pH range (3-8).

Numerous stems have purple spots and can grow 1-2 me tall, the mature canes are hollow. Leaves are dark green in colour and arrange alternately along the stem. Flowers are small and white.

Never purchase this plant or attempt to grow it. Soil containing root fragments can contribute to its spread.

Information provided by Alberta Invasive Plant Council

Resources

2011 Rural Municipality Distribution Map

2010 Rural Municipality Distribution Map

Japanese Knotweed MWSA 2009 Survey Map

Alberta Invasive Plant Council Fact Sheet

Back to Terrestrial Invasive Species List

Invasive Species Council of Manitoba

Japanese Knotweed

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