Outsidepride Butterfly Bush Plant Flower Seed Mix - 200 Seeds Butterfly bush mix is a perennial flowering bush which grows in USDA zones 5 - 9. This beautiful flowering bush can reach 8 feet in height! Start these flower seeds for a great addition to your butterfly garden. Hummingbirds may appear too, and they prefer the darker bloom colors while butterflies prefer the lighter blooms. Also called Summer Lilac or buddleia, the flower seeds can be started indoors several weeks before the last frost. Sow 3 - 4 seeds per plant to begin attracting butterflies.