Japanese knotweed spreads along Centennial Trail

September 26, 2026

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was observed 30 times in the past 30 days, concentrated along the Centennial Trail and streets near Lake Stevens between September 3 and September 23, 2026.¹ This invasive species flowers late summer through fall and spreads aggressively along disturbed corridors, persisting despite management efforts in the region.¹

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