February Perennial of the Month-Northern sea oats

The seed heads of Northern sea oats (Chasmanthium latifolium) seem to whisper in the fall and winter on the slightest breeze. The attractive seed heads are uniquely flat, unlike their fellow fuzzy-headed cousins in the grass family. The graceful arch of the heads on the long, slender stems works well in late-season or dried floral arrangements. 

Northern sea oats are a host plant for some native skipper butterfly caterpillars and moths and are eaten by seed-loving bird species.

This native grows along moist stream edges or wetlands. In the garden, it prefers moist, well-drained soils but tolerates mild drought conditions and poor soils. Full sun to part shade is preferred. Northern sea oaks typically grow 2-4′ high, forming a clump that spreads by seed and underground rhizomes. The happier the plant, the more it spreads. Keeping it in the shade and a little on the dry side seems to control its sometimes-aggressive attitude.

The seed heads also provide winter interest with a texture complementing other grasses and evergreens in the winter garden. For this reason, it’s best not to cut them down until late winter to enjoy the sights and the sounds.

What I love about this plant;

-It’s a native!

-High pest and disease resistance.

-Deer resistant!

-Works for naturalizing, erosion control, and problematic wet spots in the landscape.

What’s not so great;

-Depending on the growing conditions, sea oats can be aggressive in the garden, spreading by seed and rhizomes. Dry or heavy shade conditions help limit the spread.

Comments or questions? Email Garden-Lou at gardenloustl@gmail.com

Words and photos by Jo Batzer

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