Spring is slow coming this year, but as a result we recently had on our carport/roof/feeder a huge flock of redpolls, the sparrow-like birds which “irrupt” every other year or so from the far north.
Hanging Dams are the answer
If it’s knot-weed, what is it? It’s not bamboo, for one thing, though it grows like it. It is the very thick shrub which is blooming in thin white arches right now along roadsides.