Native Roadside Wildflowers in Rural Areas: Developing Best Management Practices for Establishment of Plantings by Seed and Enhancement of Naturally-Occurring Populations

The main goal of this study was to determine the effects of competition and mowing on native wildflower establishment on roadside right-of-ways (ROWs) dominated by bahiagrass (Paspalum notatum). The species were Florida ecotypes of Coreopsis lanceolata, C. leavenworthii, Gaillardia pulchella, and Ipomopsis rubra. Bahiagrass competition was the main factor limiting establishment of wildflowers under simulated ROW conditions. The optimal establishment method was to spray sites twice with glyphosate in the fall (2 weeks apart, with final application 2 weeks before seeding), mow the site a few days prior to seeding, and remove excessive thatch and clippings. Short-term sustainability was not affected by mowing two to six times per year, when timed to avoid flowering and seed set. Frequent mowing (12-24 times per year) that did not account for flowering and seed set reduced the fitness and growth of C. lanceolata and C. leavenworthii. Based on costs, aesthetics, safety, and management practices, establishing new plantings of Florida ecotype native wildflowers by seed is cost-effective for rural ROWs that require mowing by small to medium-sized mowers or string trimmers. However, preserving existing stands of native wildflower plantings is also an economically justified method of establishing new native wildflower plantings on all ROWs. Results of the study suggest that aesthetically appealing stands of Flaveria linearis in south Florida can be established provided that F. linearis covers at least 20% of the ROW site, and mowing frequency is substantially reduced and times to maximize natural reseeding.