Details of...
Scientific Name: Fallopia japonica ( syn. Reynoutria )
Pronunciation: fal-OH-pee-uh juh-PON-ih-kuh
Common Name: Japanese knotweed
Family Name: Polygonaceae
Plant Type: Invasive plant, Shrub - deciduous, Herbaceous perennial, Weed (horticultural)
Key ID Features: Stems hollow, bamboo-like, arising from rhizomes; leaves have a straight base (truncate), apex with an abruptly pointed tip, undersides have small ridges or bumps on veins or margins, up to 17 cm long; florets creamy-white, 2-3 mm wide, in panicles arising from leaf axils that are about 15 cm long. (Giant knotweed, F. sachalinensis, is very similar but larger).
Course(s): Level 2 Apprenticeship

Habit: Upright
Form: Oval - vertical, Round
Texture: Medium - coarse
Mature Size:
Height:2 - 3m
Spread:7 - 10m
Growth Rate:Fast
Hardiness Rating: Zone 5: (-29 to -23 C)
Exposure: Deep shade, Filtered shade, Full sun, Part sun/part shade
Soil/ Growing Medium:
Water Use: Moderate
Landscape Uses:
Additional Info: Google (another synonym commonly in use is Polygonum cuspidatum). Compare to giant knotweed giant knotweed (F. sachalinensis), Bohemian knotweed (Reynoutria × bohemica), and Himalayan knotweed (Persicaria wallichii) which are also invasive in B.C.
Japanese knotweed
Leaf Morphology: Glossary
Form: Simple
Arrangement: Alternate
Texture/ Venation: Soft flexible
Surfaces: Glabrous
Colour in Fall: Orange
Leaf(let) Terms:
Shapes: Ovate
Apices: Acuminate
Bases: Truncate
Margins: Entire

Inflorescence Type: Floriferous, Panicle
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
(LTW) Langley Township Walk : Glover rd. coffee shop
(NCA) Not Currently Available : needed
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