Quick Answer
Japanese knotweed is recognised by bamboo-like stems, shield-shaped leaves, and white flower clusters in late summer.
Identification Checklist
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Stems: Hollow, green with purple flecks.
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Leaves: Heart-shaped, arranged in zig-zag pattern.
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Flowers: Creamy-white clusters (Aug–Sept).
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Growth Rate: Up to 10cm/day.
Seasonal Appearance
| Season | Appearance |
|---|---|
| Spring | Reddish-purple shoots emerge |
| Summer | Dense green foliage, bamboo-like stems |
| Autumn | White flowers, leaves yellow |
| Winter | Brown, brittle canes |
FAQ
Q: Can knotweed be confused with other plants?
A: Yes — it’s often mistaken for bindweed or Russian vine. A survey confirms identity.
Q: Does it die in winter?
A: Stems die back, but rhizomes stay alive underground.
About the Author
Written by R L Roberts, PCA-accredited invasive weed specialist and author of “Japanese Knotweed in America.”
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