Butterfly weed, scientific name Asclepias tuberose, germinates easily from seed, according to the Rickert’s Garden website. Start butterfly weed seeds either in late summer, around August, or in the spring outdoors or indoors. A member of the milkweed family, butterfly weed is hardy to zones 3 through 10.
A period of damp, cool stratification is required to promote fresh butterfly weed seed germination, according to the Richert’s Garden website. Stratification involves placing the seeds in moist peat moss and refrigerating for 10 to 12 weeks, which breaks the dormant period. This is not necessary with older seeds. After stratification, plant the seeds directly outside or grow them indoors until the plants develop five to six leaves. At that time, move the seedling plants outdoors to a permanent location. Keep the seedling moist until well established. Butterfly weed seeds planted in the fall will produce moderate blooms the following spring; however, they generally will not bloom in full until the following year.
Butterfly weed is a perennial, sprouting each spring from the same roots and forming an expanding clump. Growing up to 3 feet in height, the butterfly weed blooms most of the summer and late in the season. Bright-orange, tiny flowers occur in clustered flowerheads on each stem, according to the American Meadows website. Butterfly weed grows best in full sun but does tolerate some shade and is native to most regions of North America, from Canada to Florida. Requiring sandy soil and draining conditions, butterfly weed is also adaptable to arid conditions.
Butterfly weed seeds come in a few color varieties, including the pure white flowers of the milkmaid, according to the Swallowtail Garden Seeds website. The soulmate produces flowers in a deep rose-pink color and the butterfly weed seeds feature the standard orange-colored blossoms. Also available in a variety called gay butterflies, these seeds are in shades of yellow, orange, red and bronze, all in one plant. All the different varieties grow to the standard 3 inches in height and bloom throughout the summer months.