Impact of species selection on plant community, sod tensile strength, and translocation rooting of a pollinator-garden sod

Abstract

Interest in pollinator gardens is increasing to address pollinator decline. The establishment of perennial native plants often takes a few years and establishment projects are often lost to competition from unwanted weedy vegetation. Mature sod of pollinator-serving, native plants that is free of weeds would be highly desirable to conventional turfgrass sod consumers, thus offering a new revenue stream for traditional sod producers. The objective of this study is to evaluate the influence of four foundational species treatments on 3-year floral biodiversity of pollinator-serving plants, sod tensile strength, and transplant rooting strength. Results suggest that polycultures of pollinator-serving forbs can produce a marketable sod with sufficient tensile strength for lifting and translocating and sufficient ability to establish once relocated. Sod tensile strength, however, is insufficient for lifting when the plant community is not grown over plastic or does not contain a high-shoot density or rhizomatous foundation species such as hard fescue (Festuca longifolia Thuill.) or common yarrow (Achillea millefolium L.). Unfortunately, adding hard fescue or common yarrow markedly reduces the Shannon diversity index and species richness. The force needed to lift transplanted sod after 3 months was 5553 to 6969 N m-2 regardless of foundation species treatment and was numerically higher than the force reported by previous researchers to lift sod of various turfgrass species. Collectively, the data suggest that the best balance between preserving floral biodiversity and maximizing sod handling integrity would be approached by establishing pollinator-serving forbs alone or with a blend of native grasses over plastic. Mature, weed-free sod of native pollinator-serving plants offers a potential new revenue source for sod producers. Polycultures of pollinator-serving forbs yielded marketable sod with good tensile strength and transplant success. Optimal floral diversity and sod handling is achieved by planting forbs alone or with native grasses over plastic.