Butterfly weeds are best known for their colorful flowers and foliage that attract butterflies and caterpillars. This plant is considered a low-maintenance, perennial shrub by the Smithsonian National Zoological Park. Butterfly weeds are very hardy in USDA zones 4 through 10.
Start butterfly weed seeds in late August for flowers with the quickest blooming time. If you are planting fresh seeds, they require a cold period, where you place the seeds in a bag of moist peat moss and refrigerate for 10 to 12 weeks. If you start seeds in the spring, they will not bloom until the following year.
Butterfly weed seeds germinate within 30 to 90 days wherein they break the surface and officially become seedlings. They grow fast and will eventually max out in height at approximately 12 to 24 inches. If started indoors, wait until seedlings reach five to six leaves before transferring to a permanent location.
While mature plants will tolerate drier soils, seedlings need moist soil to establish themselves. They need a location with access to full sun and tolerate sand, loam or clay soil. If you plant more than one butterfly weed plant, space them at least 18 inches apart.