Landscaping and gardening with ornamental grasses is hot. Ornamental grasses provide home gardens with nesting sites, food, and cover for birds and other animals; pleasing and unusual texture and dimensionality; and garden interest in all four seasons. Some varieties can be used to plant lawns that require less mowing and water.
As their popularity grows, the invasive nature of some ornamental grasses is becoming a problem. If you’re planting grasses this spring, try to find native, non-invasive varieties. It’s amazing how often I see invasive plants, including grasses, at reputable nurseries. A lot of people probably don’t care, but I tend to assume that a gardener who bothers to patronize a real nursery instead of his or her local big-box gardening center actually cares about what they’re planting. Don’t assume that just because a “good” nursery carries a plant that it’s not invasive. Unfortunately it isn’t always so.
Some invasive ornamental grasses commonly found in nurseries are:
- Pampas grass (Cortaderia selloana, C. jubata)–This stuff is everywhere. If I had grown up in the kind of neighborhood that had a homeowner’s agreement, there would have only been one rule: All homeowners must plant a mound of pampas grass beside their mailbox. Pampas seeds and spreads prolifically and is invasive in California and Hawaii, and is banned from sale in South Africa and New Zealand.
- Maidengrass (Miscanthus spp.)–It’s really unbelievable how many so many species of Miscanthus in the nursery trade; M. sinensis seems to me the most common and there are a billion different cultivars. I’ve read various advice that some species and/or cultivars are invasive and others aren’t: variegated ones are a problem; antique species aren’t invasive; depends on when in the growing season that they bloom and drop seed, etc. Personally, that’s too much to information for me to sift through. I realize that it’s an important landscaping plant, but I just wouldn’t buy Miscanthus spp. anymore. I’m sure many will disagree.
- Reed canary grass or ribbon grass (Phalaris arundinacea)–in the wild P. arundinacea is a wetland invasive; a couple of white-striped cultivars are sold in nurseries.
- Fountain grass (Pennisetum sp.) Like maidengrass, there’s a lot of hearsay on what’s invasive or what’s not. XYZ species is OK; ABC is not; It’s OK as long as you cut it back before it seeds; on and on. I’m too lazy–I just don’t buy it.
Don’t forget that invasive is in the eye of the beholder; in other words, what’s native and lovely in one growing zone might be invasive somewhere else. An example of this is the native grass river oats, Chasmathium latifolium; there are many other examples as well. Do your research before you buy. A lot nursery owners and workers that I’ve talked to don’t know or don’t have time to find out the answers. So I’d ask a local extension agent, call your local Master Gardener hotline, or look it up on the Internet–but be sure to use a non-commercial source SPECIFIC TO YOUR AREA such as a university with a cooperative extension/outreach program. Rick Darke’s excellent volumes, The Pocket Guide to Ornamental Grasses and The Encyclopedia of Grasses for Livable Landscapes are great resources as is the venerable Bill Cullina’s Native Ferns, Moss, and Grasses: From Emerald Carpet to Amber Wave, Serene and Sensuous Plants for the Garden.
Here are some native non-invasives that I like:
- Feather reed grass ‘Karl Foerster’ (Calamagrostis x acutiflora ‘Karl Foerster’). This upright grass is tolerant of a wide range of conditions and rarely self-sows.
- Little bluestem (Schizachyrium scoparium). The foliage of this prairie grass is various shades of gray-blue-green and turns orange, red or tan in the fall.
- Muhly grass (Muhlenbergia capillaris). I love this stuff (photo above). It’s like fluffy pink clouds.
- Pennsylvania sedge (Carex pennsylvanica). This sedge would be good to use for a path or lawn replacement. It’s short clusters spread slowly, forming a thick, lush carpet (see photo below).
Switchgrass (Panicum virgatum). Ah, switchgrass. Remember when Resident Bush actually said the word ‘switchgrass’ in his 2006 State of the Union speech? I thought my head was going to spin right off my neck. Switchgrass is a tall and tufted native that’s highly touted as a potential biofuel crop. (Because, as George so deftly put it, “America is addicted to oil.” Thanks for the insight, shrub!)
- Buffalograss (Buchloe dactyloides). What’s not to love? Another prairie grass, Buffalograss is short and drought-resistant, and would be an earth-friendly alternative to a traditional lawn.
- Muhly grass courtesy of Rick Darke and HDTV
- Pennsylvania sedge courtesy of Cornell Extension All Star Groundcovers