25 Fresh Seeds Butterfly Weed Butterfly Milkweed (Asclepias tuberosa) is the host plant of the monarch butterfly and an important nectar source for bees and butterflies. The bright orange blooms stand-out against any other colour in the garden. It is less toxic than it's cousin Common Milkweed, has more of a shrub-like habit and spreads less aggressively. Growing Instructions Cold, moist stratification required. Mix seeds with moist substrate (vermiculite, perlite or moss) and place in a plastic bag and refrigerate for 6-8 weeks. Sow seed at 1/8 inch depth. Do not let seedling dry out while it is establishing. OR Sow directly outdoors in late fall to overwinter.