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Japanese Knotweed
Japanese Knotweed botanical plate
Field guide plate · click to zoom

Japanese Knotweed

Reynoutria japonica
In the United States: Invasive
Listed as invasive. Check local regulations — several jurisdictions restrict planting.

Japanese knotweed produces abundant nectar from its creamy-white flower panicles in late summer, providing a valuable late-season resource for honeybees when other forage is limited and sometimes yielding monofloral honey. The plant is a vigorous herbaceous perennial that spreads aggressively via rhizomes to form dense stands. Bees visit the flowers readily for both nectar and pollen.

Nectarhigh
Pollenlow
Bloom (US) August–September
Duration~45 days
TypePerennial
Sunfull

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