Establishment and management of native wildflowers on Florida roadsides and former pastures

Establishing native wildflowers into areas dominated by Paspalum notatum var. saurae (bahiagrass) is a common goal of roadside management and ecological restoration. Yet, there is limited information on establishment and management practices for local ecotype seeds. This research sought to determine the effects of competition and disturbance on native wildflower establishment in areas dominated by P. notatum .Effects of planting season and post-planting disturbance (cutting) were assessed on competitive interactions between P. notatum and two Florida native congeners, Coreopsis lanceolata (lanceleaf tickseed) and C. leavenworthii (Leavenworth's tickseed) in two-species competition experiments. Coreopsis survival was greater in fall- than spring-established plants. In fall-established plants, C. lanceolata had higher survivorship than C. leavenworthii , although C. leavenworthii biomass and flower number were greater than that of C. lanceolata. Paspalum notatum reduced C. lanceolata biomass 58% and C. leavenworthii biomass 41% however, conspecific neighbors reduced biomass of both Coreopsis species by at least 81%. Cutting decreased above- and belowground Coreopsis biomass by 55% and 30%, respectively.Seed and microsite limitations to establishment were assessed by seeding C. lanceolata at 100, 600, and 1100 live seeds/m2 and altering microsites with disturbance (none, sethoxydim herbicide, glyphosate herbicide, topsoil removal) and irrigation (none, pre-seeding, pre- and post-seeding) treatments. By the end of the study, microsite limitation was greater than that of seed limitation with greater C. lanceolata establishment in the glyphosate treatment than other disturbance treatments. Coreopsis lanceolata establishment was limited when seeded at 100 seeds/m 2 but not at 600 seeds/m2. Seeding at 1100 seeds/m 2 provided little increase in establishment compared to 600 seeds/m 2.Effects of pre-planting herbicide treatments (none, glyphosate, imazapic) and post-planting mowing frequencies (two and six times/year) were assessed for three wildflower species (C. lanceolata, C. leavenworthii, and Gaillardia pulchella (firewheel)) on simulated roadsides at three sites in Florida. The glyphosate treatment resulted in greater wildflower establishment than the imazapic and control treatments. The imazapic treatment improved establishment of C. lanceolata only, which also had moderate cover in the control treatment. Mowing frequency did not affect wildflower percent cover or seed bank density, perhaps because mowing was reduced during wildflower blooming and seed dispersal.