Japanese knotweed fruiting along Pittsburgh waterways

October 5, 2026

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was observed with ripe fruits on 2026-09-29 and recorded 14 times across Pittsburgh in the past 30 days.¹ Fall is the species' primary seed dispersal window; plants spread via rhizomes and also by seed, so ripe fruits in the waterside and urban locations where the species concentrates substantially increase its propagation potential.²

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