Butterfly milkweed seed is sold in quantities of 25, 50, or 100. Seed has better germination with cold stratification.
Butterfly milkweed is well-known these days for its importance in the life cycle of the Monarch butterfly.
It is also a well-documented medicinal plant. This is particularly so of the root, which gives the plant the name pleurisy root in herbal medicine circles.
Seed comes dry and requires cold stratification for best results.