Stratification and perigynia removal improve total germination and germination speed in 3 upland prairie sedge species

Abstract

Sedges are a substantial and important component of many remnant tallgrass prairies but are often underrepresented in prairie restorations due to challenges associated with establishment, cost, and availability. Improving planting practices can mitigate some of these challenges, making it more cost-effective to include sedges in prairie restorations. In this study, we examine the effect of cold-moist stratification and perigynia removal on germination of 3 common and abundant upland sedge (Cyperaceae) species: plains oval or shortbeak sedge (Carex brevior (Dewey) Mack.), field oval or troublesome sedge (C. molesta Mack. ex Bright), and prairie or Bicknell’s sedge (C. bicknellii Britton). These species are highly practical candidates for prairie, roadside, and pollinator habitat restoration. We automated perigynia removal using a commercial brush machine to ensure applicability to large-scale restorations. Both stratification and perigynia removal improved total germination and germination speed, but there was no benefit to applying both treatments in combination. In general, stratification improved germination speed more than perigynia removal, but both treatments increased total germination by the end of the 84-d trials to comparable degrees. Stratification and perigynia removal were particularly beneficial for C. brevior and C. bicknellii, improving total germination by up to 40% in these species. Based on these results, we recommend fall seeding during restoration as a natural cold-moist stratification technique, and perigynia removal for spring-seeded restorations.