Mow, till, combo, or nothing: Exploring best fall management practices for pollinator plantings

The USDA provides funding for landowners to plant wildflower plantings for pollinators. The USDA recommends mechanical management of plantings in the fall to halt woody encroachment and maintain blooms for pollinator forage. However, empirical studies about how these practices impact foraging bees (Hymenoptera: Anthophila) are lacking. Our goal is to determine the effects of common fall management practices on the density and diversity of planted wildflower blooms and foraging bees in the southeastern USA. In this study, we evaluate mowing, light disking, or a combination against a no-management control. In April 2022, we planted twenty species of wildflowers at three sites in Shorter, Alabama. In fall of 2022 and again in fall of 2023, we applied the treatments in a randomized block design to 16 subplots per site (n=48). Throughout the growing seasons of 2023 and 2024 (May – October), we surveyed vegetation and visiting bees. In each subplot, we counted open blooms of planted species in ten 1-m2 quadrats and actively netted bees visiting flowers along two 10-m transects in the morning and afternoon. We found that total bloom and bee density do not differ among the treatments, yet wildflowers exhibit per-species responses to the treatments. Compared to control, the number of Dracopis amplexicaulis blooms decreased by over 80% in all managed treatments whereas Achillea millefolium had two times as many blooms in mowed treatments in 2024. These results will help to establish recommendations on how to best manage wildflower plantings to provide forage for pollinators.