Plant Gay Butterflies Butterfly Weed in well-drained soil with full sun exposure. Space plants 18-24 inches apart. Water regularly during the first growing season to establish a deep root system, then reduce frequency. Fertilize with a balanced, slow-release fertilizer in early spring. Deadhead spent flowers to encourage more blooms. Cut back stems in late fall or early spring to promote healthy growth. Protect from pests like aphids and spider mites with insecticidal soap if necessary.