Knotweed Polygonum aviculare Knotweed is an annual weed that prefers the hard, heavy-traffic areas and the compact soil next to driveways or streets. It sprouts in spring with the first warm temperatures, and the seedlings are often mistaken for new grass plants. However, it soon branches out and forms a tough wiry mat that crowds out grass.
Leaves are blue-green in color.
Once it reaches maturity, it can not be selectively controlled, other than by hand pulling.