IN THE WAY THAT PINE CONES fascinate me, I’m taken in by the seedheads of Northern sea oats, too—and actually, they’re a little bit like a flattened cone, aren’t they? One of three shade-tolerant ornamental grasses I grow, Chasmanthium latifolium is an American native. Chasmanthium latifolium, up close:
Northern (also called upland, or inland) sea oats is native to Eastern North America, says the Lady Bird Johnson Wildflower Center, specifically “from PA south to n. FL, west as far as s. IL, e. KS, and central TX,” and into northern Mexico. It’s easy to grow, and some birds enjoy its seeds, as do small mammals. Me, too.
Chasmanthium likes a semi-shady to shady spot where the soil is moist, and it can even take poor drainage. This is a low-maintenance plant suited to that hardest of spots–a shady slope—because sea oats forms strong, widening clumps, and also reseeds (some gardeners in certain locations say it does that too much; not true here). Don’t plant it in baking sun (I have had it do well in half-day sun where the soil moisture was good), and give it a bed of its own, or with other strong growers.
Its slightly blue-green foliage, which resembles a low bamboo’s and by high summer is more green than blue, sprouts early in springtime, reaching about 2 feet tall for me (and taller in some environments), arching and attractive. In fall the foliage goes bright yellow, at about the same time the seedheads (which start off green in summer, and fade to pale tan, bouncing all the while on wiry stems) go bronzy-coppery tones before turning brown. I leave the plants up in winter, to get the most from the display and any wildlife value, and clean them up during a thaw in February or March—the same way I treat bigger Asian ornamental grasses such as Miscanthus and Pennisetum.
Wondering what my other shade-tolerant ornamental grasses are? Gleaming golden Hakonechloa macra ‘All Gold’ is one (knee-high, part shade), and the thuggish green-and-white showy one called gardener’s garters that I’ve had 20 years and managed to keep in one little spot somehow, Phalaris arundinacea ‘Picta.’