1[mass noun] A plant of the dock family, which typically has sheaths where the leaves join the stems and is often an invasive weed.
- ‘Abundant goosefoot, some knotweed (both erect knotweed and other species), some wild rice, and seeds of various grasses and weeds were also recovered.’
- ‘Dock-leaved knotweed appeared in 1998, and overwhelmingly dominated the submergent littoral zone in 1999.’
- ‘Barberry, knotweed, and ailanthus are just some of the horticultural immigrants that continue to out-compete many of our indigenous species.’
- ‘A knotweed is so called because its roots are knotted or twisted; bistort means twice twisted.’
- ‘Another plant that has done well in our garden this year is a knotweed, labelled Persicaria filiformes ‘Variegata’.’