Seeds from this butterfly plant Blood Flower Asclepias Curassavica. They blossom in zones 4-11 throughout the season and will bring more butterflies than you can imagine. These plants are tender perennials and grow in full sun and sandy soil is best for them. Quite a drought tolerant plants and is a real attraction in the garden with its bright orange and tangerine blossoms. 4-6 weeks of stratification suggested for good germination. We recommend that tropical milkweed, which can be generally called Asclepias curassavica, should be cut back in the winter and fall months in the southern U.S. and California.