Investigation of Carex: A look at seed dormancy, use as a low input lawn, and local stand characterization
Abstract
Carex has been an underutilized genus across multiple industries due, in part, to poor germination resulting from a strong primary dormancy. Dormancy can usually be broken using stratification or plant hormones, but the optimal stratification conditions have not been described for many Carex species. Therefore, our objectives for this research were to make observations on the most efficient way to improve seed propagation in local species. A 2-year study was conducted to improve germination and decrease time until germination in Carex blanda (common wood sedge), C. brevior (oval plains sedge), C. eburnea (ivory sedge), C. muskingumensis (palm sedge), and C. pensylvanica (Pennsylvania sedge) by testing germination in two soil temperatures, seven stratification lengths, and three concentrations of the plant hormone gibberellic acid (GA3). A germination improvement study was conducted in-between years to determine if seed depth improved germination for the three worst performing species. In the primary study, common wood sedge performed the worst in both years averaging ≈2% germination, and palm sedge performed the best with ≈70% germination. For the germination improvement study, light with a surface level seed depth contributed most to improved germination in the three species tested. Stratification treatments influenced both germination rate as well as time until germination. Planting depth and stratification were important in increasing germination for the majority of species, and is suggested to further improve marketability. Consumers have shown preference for low input turfgrasses that have tolerance to both shade and drought stresses. Carex species and nimblewill (Muhlenbergia schreberi) are native plants adapted in Oklahoma and may have potential as alternatives to popular turfgrass species in dry shaded environments. To evaluate the potential for native perennial ground covers common in dry woodland ecosystems in Oklahoma, a multi-location field trial was conducted in Stillwater and Perkins, Oklahoma. Four species of Carex [C. amphibola (gray sedge), C. leavenworthii (Leavenworth’s sedge), a dwarf cultivar of palm sedge named ‘Little Midge’, and C. texensis (Texas sedge)] and two sources of nimblewill were used for the study. These alternative turfs were compared against Zoysia japonica ‘El Toro’ (Japanese lawngrass) and Cynodon dactylon ‘Riley’s Super Sport’ (bermudagrass), which served as representative standards. In 2020, plant materials were established as a randomized complete block. In 2021, irrigation treatments (irrigated or not irrigated) were randomly assigned to plots using a split plot structure. Data quantifying growth was measured monthly during the growing season. By the end the second growing season, the conventional turfgrasses outperformed each Carex species and nimblewill. Most Carex showed excellent persistence but lacked the ability to spread quickly enough by the end of the two-year trial. This study demonstrated Carex species and nimblewill have potential to be grown in low maintenance lawns but need unique management practices to be efficient.
Collections
- OSU Theses [15752]