Monarch caterpillars must have milkweed to survive and this plant is an allstar! Beautiful in the home garden with a wonderful sweet and earthy scent. It spreads by seed, not rhizome so it stays put unlike Common Milkweed which can be a challenge to contain in the smaller yard. Also significant is that monarchs lay eggs equally on this plant and common milkweed. If you have a small yard and are hesitant to plant common milkweed, this is a must!