Scientific Name(s)

Reynoitria japonica R. sachaliensis or Polygonum cuspidatum

Common Name

Japanese Knotweed

Type

Herbaceous perennial

Description

6ft tall with cane like stem. Heart shaped leaves large. Tiny sprays of flowers late summer. Creeping stems

Habitat

Roadsides. Railways banks, Riverbanks.

Folklore

Edible shoots, delicacy in Japan Introduced from Japan after WW I.

Soil Type

All

Soil Fertility

All

Soil Moisture

All, prefers moist.

Soil pH

3.5 to 8

Sunlight

Full sun

Success

Vigorous underground stems supress all other growth. Small pice s of stem reproduce. Seeds remian dormant for long periods, will travel down rivers.

Importance

A serious notifiable weed in waste ground and riverbanks, smothering all native wildflowers

Cultural Control

Cultural (1.5) and (1.6) every week over several years. All Preventative (2.1 to 2.8)

Chemical Control

(3.1.1a) when mature in mid summer.