Oklahoma State University Turfgrass Science

Carex Sedges and Other Alternative Plant Materials for Shaded lawns

presented by Godwin Shokoya and Dr. Charles Fontainer

Growing quality turfgrasses in dry shade is a consistent struggle in parks, golf course roughs, and home lawns. Shade tolerant grasses like tall fescue and zoysiagrass can do well if irrigation and soil fertility is maintained. However, for those of us who want something different, low input, and mowable, there are not many options in the marketplace. A quick walk through the Botanic Garden arboretum and you can see various species in the genus Carex that create a near monostand in the low input shaded environment. Similar observations can be made in many low input lawns or parks having shade and dry sandy soils. Several species of Carex are sold in the nursery trade as ground covers, but we had interest in knowing what it takes to create an Oklahoma Carex lawn.

We started with a project to evaluate commercial sources of four main Carex spp (C. leavenworthii, C. texensis, C. amphibola, and C. muskingumensis) under irrigated and non-irrigated shade plots. Plots were mowed at 4-inches and observed for establishment rate and overall quality as a lawn. Initial findings were C. leavenworthii is the most promising species in terms of leaf texture, establishment rate, and overall vigor in this environment. Establishment from plugs may require excessively close spacing to achieve adequate coverage for any of the species, so further work on seed, sprig, sodding is needed. Interestingly, seed harvested from these local sites resulted in upwards of 75% germination after a cold stratification period, suggesting seed propagation may be feasible. More work needs to be done to verify effects of year, harvest date, and stratification requirements of these native populations before reliable recommendations can be made. 

Another phase of our project has resulted in a collection of over 30 specimen plants in an attempt to identify which species are most common in our low input shaded landscapes. The majority of these plants appear to be C. leavenworthii, which reinforces our field study findings that this species can do well in our environment. The plot in front of you (F8) is a single space plant nursery installed in late summer 2021 with plants either purchased from commercial sources or collected from various locations in the south-central US. Species include C. leavenworthii, C. pensylvanica, C. texensis, and a group of plants we suspect are actually in the Kyllinga genus.  Feel free to make note of variation in color, tillering, and flowering among these selections.

F8 Plot Plan - Notes on entries in the following graphic


Notes on F8 entries - Plants collected from various shaded locations in Texas and Oklahoma.

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