Questions concerning wildflower usage on Indiana highway rights-of-way were investigated. Native prairie wildflower seed quality was found to be highly variable among supply companies, species, and years. Less variability was found among “garden” wildflower species and suppliers. Direct seeding was found to be successful with six species of native prairie forbs: Butterfly Milkweed Asclepiads tuberose, Wild Bergamot Monarda fistulosa, New England Aster Aster novae-angliae, Pale-purple Coneflower Echinacea pallida, Gray-headed Coneflower Ratibido pinnota, Ironweed Vernonia fasciculosa. Five species of “garden” wildflowers performed well: Common Cosmos Cosmos bipinnatus, Yellow Cosmos Cosmos sulphureus, Cornflower Centaurea cyanus, Goldenwave Coreopsis sincioria, Black-eyed Susan Rudbeckia hiria. Significant variation was found for species establishment success with respect to soil type. Seeding transplanting was found to be a successful method for establishment of forb species, especially those that are difficult to establish by direct seeding. Eight-inch deep seeding tubes increased plant survival compared to plants produced in five inch deep tubes. Use of water-holding polymers in the growing medium, or inoculation with vesicular-arbuscular mycorrhizal fungi did not improve forb transplant survival. YAM inoculation did result in larger plants after the first growing season. The cost of establishment and management of wildflowers varied with the type and management strategy. Wildflowers were found to be cost-effective when compared to the current grass monoculture vegetation strategy used by INDOT. “Garden” wildflowers were more costly initially, but became cost effective when low, long-term management costs were factored into the analysis.

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prairie, native plants, forbs, establishment, direct seeding, transplants, timing of planting, mycorrhizae, VAM, water holding agents, seed quality, HPR-2075

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Performing Organization

Joint Highway Research Project

Publisher Place

West Lafayette, IN

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