Site Preparation and Planting Strategies to Improve Native Forb Establishment in Pasturelands

Increasing the diversity of native forbs in pasturelands can benefit insect pollinator populations, which have been declining widely. Establishing native forbs into existing pasturelands can be challenging, however, and information about effective planting strategies in these systems is lacking. In this study, we evaluated several planting strategies to improve native forb establishment. Two field experiments were conducted in Virginia, USA in 2021 and 2022. Experiment 1 evaluated how six herbicide treatments and tillage affected establishment success when forbs were planted in summer or fall. Experiment 2 investigated how different seeding rates from 2.2 to 56 kg/ha and pre-seeding cold stratification affected forb establishment. In experiment 1, treatments using Roundup/glyphosate and tillage resulted in the most forb establishment. Planting in summer improved establishment with Roundup/glyphosate application. In experiment 2, native forb plant establishment was positively associated with seeding rate (p < 0.001), with a rate of 56 kg/ha resulting in almost 3x more forbs compared to the lowest seeding rate. Cold stratification also increased target plant establishment (p < 0.01), but these effects were inconsistent among species. Our results suggest that effective native forb establishment can be achieved through intensive site preparation with Roundup/glyphosate or tillage to suppress vegetation and planting at rates no higher than 11 kg/ha.