A tall grass for shade gardens

Chasmanthium latifolium, commonly called northern sea oats, comes to the rescue of ornamental grass-starved shade gardeners.

Most ornamental grasses are sun worshippers, often leaving shade gardeners longing for the structure, texture and movement that only grasses can provide in the landscape. While northern sea oats is content growing in a partly sunny landscape, it is one of the most shade tolerant ornamental grasses.

Northern sea oats are native to southern Illinois where they grow in rocky areas along streams, in moist meadows and woodlands, and in river floodplains. Hardy throughout the state, they prefer to grow in average to moist, well-drained soil in our gardens.

Northern sea oats grow up to 3 feet tall in my garden but can reach as tall as 4 feet if they are given optimum growing conditions. Sporting foliage often mistaken for bamboo, their blue-green, arching leaves in spring become more green than blue in summer.

In fall, the foliage turns yellow before fading to brown for the winter. Left standing, northern sea oats offer interest in the winter landscape and extra insulation for the plant itself. It should be cut back to the ground in early spring before new growth begins.

What makes this ornamental grass special, besides its ability to grow in partly shaded conditions, is its seed heads. In summer, clusters of oat-like seed heads emerge green, fade to tawny beige and turn copper-colored by fall. Summer breezes tickle them and when backlit by the setting sun, they positively glow.

Northern sea oats has a reputation for aggressive self-seeding, but I have not experienced it in my garden. The mulch is thick in my garden and may prevent seeds from reaching the soil in order to germinate. Or perhaps the birds and other small animals eat them before they have a chance to fall.

If self-sowing is a problem, deadheading their seed heads before they have the opportunity to spew their seeds about the garden will solve the trouble. Cut before they are fully mature, seed heads are beautiful in cut flower arrangements - or let them mature and use them in dried arrangements.

Chasmanthium latifolium is easy to grow, rarely suffers from attacks from insects or disease, and adds a vertical accent to a partly shaded border. Consider adding it to your list of must-get perennials next spring.

• Diana Stoll is a horticulturist, garden writer and the garden center manager at The Planter's Palette in Winfield. She blogs at gardenwithdiana.com.