Q: I’m happy to try a lawn alternative for my shadier areas but I’d like it to look more like a lawn than a groundcover or mix of flowering plants. What kind of grasses work for that?
A: Not many true grasses will grow well if you have less than full sun, but several perennials that look like grasses can work nicely. My primary recommendation would be to try one or more species of sedge (Carex). I was excited to see the study results for sedges from Mt. Cuba released recently: “Carex for the Mid-Atlantic Region” that may be a useful reference.
Mt. Cuba Center is a public garden and research facility in Delaware which displays and studies native plants, and they perform periodic plant trials to evaluate species and cultivars for garden performance. Lately they have been including an assessment of pollinator appeal as well, though in this particular case that wouldn’t apply since sedges are not grown for pollinator draw. (Even though the caterpillars of several of our less-often-seen butterflies feed on sedges.)
Sedges are a species-diverse group and make for an excellent grass-like aesthetic in partial shade to full shade. Many form low soft-looking tuffets, though with time or dense planting can form a more-or-less uniform “lawn.” Still, don’t expose them to much foot traffic since nothing is quite as tolerant to that as turfgrass. Well over one hundred sedges are native in Maryland, and the Mt. Cuba study results include lists of those well-suited to more sun than shade, more shade than sun, and a tolerance to mowing (not that they require it by any means).
A few true native grass species tolerate some shade, but won’t give you a comparable look to a lawn since they grow much taller or have a different leaf color or texture (often wider, coarser leaves). Examples include river oats (Chasmanthium latifolium) and Eastern bottlebrush grass (Elymus hystrix), which still could make nice accents if you wanted spots with showier seed heads.
The non-native asparagus relative mondo grass (Ophiopogon), which has dark green grassy evergreen leaves and a slowly-spreading growth habit, has been successfully grown as a lawn look-alike under mature trees. I would not recommend using its cousin Liriope, the spreading form of which (Liriope spicata) can be too aggressive and is considered invasive. (Plus, it’s way over-planted.) Mondo grass thus far does not appear to be colonizing natural areas in or near Maryland.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
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I have recently heard, or rather I was warned, that river oats (Chasmanthium latifolium), while native and lovely, tend to be exceedingly aggressive and that they dominate landscapes where they are planted. Can you comment on this please? Thank you.
This is true. River oats self-sow very easily and can spread vigorously. In some situations this characteristic may be desired (e.g., as a native competitor against invasive Japanese stiltgrass), and in some situations gardeners will cut off the seeds before they fully develop to control their spread. If this type of maintenance is not something you want, it’s better to choose something else.
Thanks so much.