Tips on Growing Butterfly Weed From Seed

Butterfly weed (Asclepias tuberosa) is a hardy, drought-resistant perennial that is part of the milkweed family. It grows 2 feet tall and 1 to 3 feet wide, blooming in early summer to early autumn. Its red-to-orange flowers attract different types of butterflies, including the monarch butterfly. Butterfly weed seeds require a cold period to bloom, which can be achieved by preparing the seeds prior to planting in the summer, or planting in the fall.

Fresh butterfly weed seeds should be planted in late August and require a period of cold treatment in order to germinate, according to Texas A&M University Extension . This can be achieved by placing the seeds in a freezer for several weeks prior to planting. Older seeds will not need a cold period to emerge from a dormant state. Plants seeds in sandy, well-drained soil, and in full sun.

Although established butterfly weeds can tolerate dry soils, newly planted seeds require adequate moisture for growth. Once the seedlings push through the ground, you can gradually cut back on water and allow the soil to dry out between waterings. Adult butterfly weeds rarely need watering, except under extreme drought conditions.

Young butterfly weed plants require extra phosphorus to encourage root development, according to online resource Backyard Gardener. Apply fertilizer containing phosphorus according to the product label when the seeds are first planted. Once established, butterfly weeds can benefit from a slow-release fertilizer that is added to the soil once during growing season. An organic fertilizer, such as fish emulsion, can also be used.

Butterfly weeds are known for being low-maintenance plants. They do attract aphids, especially on stems, according to "Cape May" magazine gardening columnist Lorraine Kiefer, but these can be removed with a steady stream of water, or left alone since they typically will not harm the plant. Removing aphids can also result in destroying any butterfly larvae that may be on the plant, she warns.

Butterfly weeds do not require major pruning; simply cut off any dead branches that you come across. Kiefer notes that butterfly weed should not be transplanted as it has a long taproot and will die if the root is damaged.