Calotropis gigantea var. purple, commonly known as Crown Flower or Giant Milkweed, is a tropical shrub native to South and Southeast Asia, prized for its striking pale purple or white waxy flowers arranged in intricate crown-like clusters. This fast-growing plant can reach 8-15 feet in height and serves as an important host plant for monarch butterflies. Seeds require warmth, proper moisture management, and mechanical scarification to achieve reliable germination within 2-8 weeks.
Before sowing
Start seeds indoors 2 months before final frost for cooler zones OR sow directly after final frost in warm annual zones OR sow in perennial zones year-round. Use heated seedling mat (75-85°F) for faster germination. Scarify and soak seeds before planting. These plants thrive in warm climates and are very drought tolerant.
Sowing
What to expect
Tips
Always scarify seeds mechanically before soaking to improve germination rates. Maintain consistent moisture but avoid waterlogging - mist regularly rather than heavy watering. Use a heated seedling mat to maintain 75-85°F (24-29°C) for optimal results. Light pressing of seeds into soil improves contact but avoid deep burial. Once seedlings emerge, provide bright indirect light and gradually increase direct sunlight exposure. These plants are drought tolerant and dislike wet feet - overwatering causes yellow leaves and root rot. Overwinter potted plants indoors in cooler zones. Handle seeds with care and wear gloves as the plant contains toxic latex. Tie organza bags over developing seed pods to collect seeds without unwanted self-seeding.
Sources: Missouri Botanical Garden, Ferri Seeds, Plant Flower Seeds, PlantVine, Wikipedia, Plants for a Future, Kew Science POWO, Multiple seed supplier resources
