Dogbane

When I saw this plant, I wasn’t sure what it was, but an internet factotum says it’s Dogbane — Apocynum cannabinum. The plant is five to six feet tall, and the bits hanging down are like hard catkins

Dogbane is poisonous — Apocynum means "poisonous to dogs" — and ingestion can cause cardiac arrest. However, some butterflies and moths feed on it, and native Americans used its fibers (similar to hemp) to make bow strings. nets, fishing line, and rope.