Fallopia japonica
Japanese knotweed
Flower Colors
Description
A tall, vigorous herbaceous perennial to 2.1m high, with cane-like stems flecked with purple, and shovel-shaped leaves borne alternately (in a zig-zag pattern) along the stems. Produces tassels of white flowers in late summer and early autumn. This plant is considered invasive, and legal requirements apply to its control
Mature Height
2.5m
Mature Spread
4m
Plant Characteristics
Foliage
Deciduous
Growth Habit
Upright
Growth Speed
Very Fast · 2.5 m/yr
Soil Texture
ChalkClayLoamSand
Soil pH
AcidAlkalineNeutral
Soil Moisture
Moist but well-drainedWell-drainedPoorly-drained
Hardiness (RHS)
H9
Hardiness (USDA)
Zones 3-9
Flowering Season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec