Set plants 12 to 15 inches apart. Choose a sunny location where the soil, which need not be particularly fertile, is well-drained. Plant the crown 2 to 4 inches deep.
Asclepias is late to break dormancy in the spring, so take care not to remove it accidentally during cultivation. Because of its extensive taproot (which helps account for its drought-tolerance), avoid disturbing established plants. Newly set out plants may benefit from a winter mulch; otherwise no special care is needed.
Zones 3 to 9