Heart-leaf Milkweed ("Asclepias cardifolia") is a species of milkweed plant. It is also known as Purple Milkweed (the species "Asclepias purpurascens" is also known as Purple Milkweed). It belongs in the subfamily Asclepiadoideae. It is native to western North America. Heart-leaf Milkweed is found in woodlands, rocky slopes, and lava flows.