Native Plant Establishment on Georgia Roadsides

Invasive weeds are a costly problem on Georgia roadsides due to limited management options and a lack of competition from roadside grasses. The introduction of species native to Georgia could reduce maintenance costs and suppress invasive weeds on roadsides, however, limited research has been conducted with these species in this environment. Field experiments were conducted in Georgia to evaluate establishment of 29 species (12 grasses and 17 forbs) established in the fall and/or spring at two seeding rates. Blackeyed Susan ( Rudbeckia hirta L.), swamp milkweed ( Asclepias incarnata L.), and indiangrass [ Sorghastrum nutans (L.) Nash] were the quickest to establish of all species, while blackeyed Susan, lanceleaf coreopsis ( Coreopsis lanceolata L.), and wild bergamot ( Monarda fistulosa L.) provided the greatest ground cover over the 12 mo experiment. At four of the five sites, up to four additional species of those evaluated established ≥20% ground cover in the spring seeding compared to fall. Species seeded in the spring also established faster during the first 4 mo after seeding. Overall, blackeyed Susan, indiangrass, lanceleaf coreopsis, swamp milkweed, and wild bergamot have the best potential, of the species tested, to establish under roadside conditions in Georgia.