- You will get 300+ Seeds of Common Smooth Ironweed Flower Seeds. - Seller Notes: “Vernonia fasciculata. U.S. Grown Seed. Tested 1/23-Germination 94%. Packed 1/23.”. - Planting Time: Perennial. - Soil Type: Poor soils, Clay, Loam, Peat, Sand. - Life Cycle: Perennial. - USDA Hardiness Zone (°F): 5 (-20 to -10 °F). - Soil pH: Neutral. - Watering: Medium. - Sunlight: Partial Shade, Full Sun. - Common Ironweed (Vernonia Fasciculata) - Prairie Ironweed has vivid purple flowers on top of 48 - 72-inch stems. It is easily grown from Ironweed seeds, provides a great bloom for the back of the flower border, and has attractive foliage until frost. Ironweed makes a great cut flower, but the leaves should be discarded before arranging as they do not remain attractive once they have been cut. Ironweed is actually a member of the aster family, with numerous 1/2-inch flower heads in branching clusters. They are a favorite nectar source for Bee's and Butterflies. It is common to find Ironweed plants in old fields and pastures in the mid-west to the east coast. Prairie Ironweed is also known as Smooth Ironweed or Common Ironweed. Ironweed plants prefer full sun and moist fertile soil but will adapt to partial sun and slightly moister or drier conditions. It can withstand periods of flooding as long as they do not last long. Ironweed is not hampered by pests or disease to any large degree. Sow Ironweed seeds directly outdoors in prepared soil. Keep seeds moist until germination. Ironweed plants are liberal self-sowers. The flower seeds easily catch in the wind. Deadhead the spent flowers if you do not want Ironweed flower seed spreading to other areas. 200+ Seeds per order. Thank You!. - Some American Native Wildflower seeds need to go through a cold winter to germinate. This plant is one of them. They do this so the seed won’t sprout in fall, only to have the seedling not make it through a cold winter. I have stratified these seeds to simulate a cold winter(stratification) This raises the germination rate considerably. Thanks for looking!!. - Vernonia fasciculata. - Perennial. - Full Sun. - Spring, soil temp 68F+. - Sow 3 seeds per plant,1/8"deep,18"apart. Keep moist. - Germination 14-21 Days. - Medium water. - Flowers are Purple. Blooms from early summer through late summer.