They also tempt us to try to dig them for our flower gardens. Butterflyweed has an enormous brittle tuber for its root, making it difficult to dig without breaking. That is one reason for leaving the plant for others to enjoy.
Plants from seeds can be bought from nurseries--or you can easily grow your own. Seeds can be planted as soon as collected. Wait until the pods are just turning brown and remove the silken parachutes form the seeds before you sow them.
Butterflyweed blooms from June-August. It is a member of the milkweed family, Asclepiadaceae. Unlike other plants of this family, its sap is not milky.