Scientific Name:
Reynoutria japonica
( syn.
Fallopia japonica
)
Pronunciation:
RAY-nu-tree-AH juh-PON-ih-kuh
Common Name:
Japanese knotweed
Family Name:
Polygonaceae
Plant Type:
Herbaceous perennial, Invasive plant, Shrub - deciduous
Key ID Features:
Stems hollow, bamboo-like, arising from rhizomes; leaves alternate, ovate, most 10-17cm long x 8-14cm wide, base truncate, apex with an abruptly pointed tip, undersides have small ridges or bumps on veins or margins, margin entire, apex ; florets creamy-white, 2-3mm wide, in panicles arising from leaf axils that are about 15cm long.
Habit:
Upright
Form:
Oval - vertical, Round
Texture:
Medium - coarse
Mature Height:
2 - 3m
Mature Spread:
7 - 10m
Growth Rate:
Fast
Origin:
S.E. Asia / Japan / China
Hardiness Rating:
Zone 5: (-29 to -23 °C)
Exposure:
Full sun, Part sun/part shade, Filtered shade, Deep shade
Soil/Growing Medium:
Water Use:
Moderate
Landscape Uses:
Additional Info:
Google (another synonym commonly in use is Polygonum cuspidatum). Compare to
giant knotweed F. sachalinensis,
Bohemian knotweed Reynoutria × bohemica, and
Himalayan knotweed Persicaria wallichii which are also invasive in BC.
Leaf Morphology:
Form:
Simple
Arrangement:
Alternate
Texture/Venation:
Soft flexible, Pinnate venation
Surfaces:
Glabrous
Colour in Fall:
Orange
Shapes:
Ovate
Apices:
Caudate
Bases:
Truncate
Margins:
Entire
Inflorescence Type:
Panicle, Floriferous
Flower Morphology:
Flowers perfect
Number Of Petals:
0
Corolla Shape:
Salverform
Ovary Position:
Superior
Colour (petals):
White
Flower Scent:
None
Flower Time at Peak:
Aug, Sep
Additional Info:
Five, petal-like sepals
Fruit Type:
Capsule
Fruit Colour:
White, Brown
Fruiting Time:
Sep, Oct
Additional Info:
Not showy
Bark Morphology:
Other
Bark or Stem Colour:
Green
Organ Modifications:
Rhizomes
Propagation:
Seed, Division - below ground parts
Pest Susceptibility:
(Pest resistant, Disease resistant)
Course(s):
- Level 2 Apprenticeship
Location(s):
- (LTW) Langley Township Walk : Glover Rd. and Duncan Way
- (NCA) Not Currently Available : needed