By Dan Segal

In March 2015, the DEC added the genus Miscanthus to its list of restricted plants. Restricted plants, and another smaller group of prohibited plants, are listed because of their track record for escaping from landscapes and becoming invasive beyond where they were planted. Theoretically, we can anticipate our future invasive species by paying attention to which ones are invasive further south of us—this is the logic, anyway. I am not a climate change denier, and it would be handy if we could just look south and plan accordingly for a known list of invasive species…but I don’t believe nature is that simple.

Whether you are happy, sad or indifferent about Miscanthus being a restricted plant, now is the perfect time for learning how to use native grasses as alternatives to maiden grass. Native grasses are not all the same — they range in size from small to medium and large, and they won’t all thrive in the same locations. But they are all deer proof! And they all bring grace, texture and seasonal color, enhancing the effect of their late summer perennial counterparts, and extending the garden season.

And because only a handful of native grasses seem to be in production, it is easy to learn what the more common species look like, where to use them and how they perform in the landscape.

All the grasses listed below are clumpers, not runners. This means that, unlike the invasive ribbon grasses, for example,
these will remain where you plant them, and their clump will just get slowly wider over time. They can all be divided, but they don’t need it, and in fact they need virtually no care—just one hard cut every year. I prefer early spring, just before new growth emerges from the ground. This way you can enjoy the foliage in winter wind and snow.

I will refer to the flowering stems -- inflorescences -- as spikes or heads even though those are not necessarily the technical terms.

little blue stemLittle bluestem (Schizachyrium scoparium). Found in dry and well-drained sites, this native grass can handle sand, sandy soil, gravel, driveway and parking lot neglect, and it will add color and grace to the landscape. Just don’t try to grow it in wet clay or very poorly drained sites, as it will eventually rot and disappear. I consider this one a knee-high species but it can grow a foot taller than that—so roughly 2 to 4 feet tall and about 2 feet wide.

This plant cmbines well with drought-tolerant and full-sun native perennials such as butterfly milkweed (Asclepias tuberosa), Rudbeckia spp. and blazing star (Liatris spp.). It also shows off well with the non-native late-blooming Russian sage (Perovskia spp.) because the summer foliage of little bluestem is most colorful in summer into fall.

big blue stemBig bluestem (Andropogon gerardii). Commonly seen in the Adirondacks and many other rocky natural areas of upstate New York, big bluestem can reach 6 feet in height but usually remains about half as wide as it is tall. It's stately and upright, with rich purple-reddish-orange-tan summer and fall foliage colors, and fine wispy white flower spikes. The foliage forms a dense clump that’s substantial even before this species goes to flower. Even though it can be seen in creek beds, remember that many seasonal creek beds have dry periods, and during those dry spells, the gravel substrate is very well drained. What does this mean? Big Bluestem is not a native grass for decidedly wet landscapes, but it will perform well in most landscapes with average or variable conditions. Very dry is not a problem, but a site that stays wet for nearly the entire season is probably not ideal. This plant is great with shrubs, because it’s so sturdy, and with tough perennials such as Amsonia, Penstemon, Monarda fistulosa and the non-native small shrub Caryopteris.

indiangrassIndian grass (Sorghastrum nutans). One of my favorite native grasses for seed collection because the flowers form silky heads soft as a puppy’s ear, and rich in brown and yellow hues. In flower, Indian grass is about as tall and wide as big bluestem (roughly 6 feet tall x 3 feet wide), but Indian grass foliage is a bit less colorful, and not as substantially dense or tall. Still, this species adds diversity, tolerates a bit more shade than most native grasses, lends a touch of grace, and the seed heads are an irresistible textural pleasure in the landscape. This plant lso tolerates relatively moist sites compared with little bluestem, for example. Try mixing it with tall perennials such as Rudbeckia, Veronicastrum or Aruncus.

prairiedropseedPrairie dropseed (Sporobolus heterolepis). Another favorite for landscape use, if conditions are right. Smaller than most native grasses seen in landscape production, this one forms a cute rounded mound of very fine-textured foliage about 2 by 2 feet and turns a warm pumpkin orange to dusky purple in fall. The flower spikes form a halo of subtle silver and beige above the leaves, and eventually the flowers lean down to the soil to drop their seed. This species is long-lived, as long as: 1) it does not get crowded out or smothered by more aggressive large perennials; and 2) the site is sunny enough. My favorite way to use prairie dropseed is in rock gardens or nearly rock-garden landscapes -- full sun, warm, and complementing stonework or gravel. This seems to ensure their longer-term survival. But try this one in the foreground or front border in any sunny landscape, give it some breathing room, and you’ll be happy. It goes nicely with short native Allium or non-native Nepeta.

switchgrass heavymetalSwitchgrass (Panicum virgatum). The standard-bearer of native grasses, because switchgrass grows over such a wide range naturally, and because it has been used in landscapes for so many years. In the New Jersey Pine Barrens, for example, this species grows in the shallow water of pond edges and in the mile-deep bone-dry sand under pitch pines. Switchgrass offers a perfect compromise between the smaller native grasses and the larger, now-verboten, Maiden Grass. Switchgrass usually reaches 5 to 6 feet tall and about 3 to 4 feet wide, but some cultivars are taller, and the unselected seed-grown strains can flop. I very, very rarely promote cultivars, but with switchgrass, I use Heavy Metal (pictured) and Shenandoah for the most part. Their forms and colors are reliable and complement each other well. They also work perfectly with so many summer blooming perennials. Like many of our native grasses from the prairie environment, Switchgrass prefers sun. It tolerates the heaviest of clay soils and can handle just about any moisture regimen, but avoiding constant saturation is good for just about any plant. We use switchgrass with Monarda, Rudbeckia, Amsonia, Liatris, Penstemon, Agastache … just about anything.

northern sea oatsNorthern sea oats (Chasmanthium latifolium) works well for part shade. It is tolerant of fairly heavy shade because it’s a floodplain species, which means this grass has evolved to grow under a tall, dense canopy of deciduous trees in sites that flood seasonally. Therefore, we can use it in wetter and shadier sites than many other native grasses. It is aggressive from seed but can be hoed or weeded if it spreads more than you’d like. This grass generally reaches about 3 to 4 feet tall and about 2 to 3 feet wide. Spring foliage is coarse and bright, light green when young, hardening off darker and firmer through summer. People often comment that this species resembles a tiny bamboo … until pendulous tan seed heads that look like oats emerge in summer. These persist through fall and into winter, offering color ornamental value. Recommended allies are native ferns, white wood aster, Cimicifuga and Delphinium, to name a few.

A grasslike relative worth noting:

juncus effususSoft rush (Juncus effusus). The rushes are round-leaved, grasslike plants found mostly in wet or even aquatic environments, but they can be highly effective in landscapes. In rain gardens, wet borders or low spots in large beds, Juncus effusus adds color, form and texture—and grows very fast, with 100% success. Dainty brown pom-pom flower heads jut sideways from part way up the stems in summer, looking like small fireworks clusters. Leaf bases are wine-red, adding some dash for these often-overlooked and underused plants. These are useful in the right environments where many grass species will fail. Plant with Caltha, blue-flag iris, swamp milkweed and any other good native wetland species.

There are many more species of native grasses worth using, but I find it helpful to begin with the ones you’re most likely to encounter, and those with easily perceived landscape value, especially if your clients are not sure what native grasses are all about! Native grasses remind us that color, form and texture are all important landscape components, and all can come from foliage—which is at least as important as flowers in our landscapes.

Dan Segal is owner of The Plantsmen Nursery in Groton.