Knotweed

Knotweed

• Bohemian knotweed
• Giant knotweed
• Japanese knotweed

Polygonum spp. (aka Fallopia spp.)

Information Sheet (PDF)

Colorado List A - Eradication required

General

• Family: Buckwheat (Polygonaceae)
• Introduced from Asia

Habitat

• Colony forming
• Found in wetlands, drainages, and rights-of-way
• Perennial shrub
• Very invasive
• Was sold as an ornamental in the past

Common Names

• Crimson beauty, Mexican bamboo, Japanese fleece flower

Plant

Vegetation

• Leaves - smooth 3 - 4 inches wide and 4 - 6 inches long, somewhat oval shaped
• Papery sheath at nodes
• Plant 10 plus feet tall
• Stems - hollow between nodes

Roots

• Rhizomes spread up to 20 feet from plant
• Roots up to 6 feet deep

Flower

• July - September
• Small, in groups that grow from leaf axis
• White

Seed

• Small, winged, 1/10 inch wide

Seedling

• Plants re-sprout from roots in the spring

Reproduction

• Plant Fragments
• Rhizomes
• Roots
• Seed

Control

Biological

• None

Chemical

• View Information Sheet (PDF)

Cultural

• Prevention
• Removal Not Recommended - If you decide to remove, make sure the entire  root is removed. Must be repeated as new plants emerge. Clip stalks in  early Spring and treat re-growth with herbicide. Bag and dispose of all  plant parts because any fragment may sprout. Do not compost or dispose  of as green waste.

Mechanical

• Burning - N/A
• Grazing - N/A
• Mowing - Not recommended. Plants will resprout.

Use all chemicals according to the manufacturer's label. No specific recommendation or endorsement is made or implied by listing methods or products.