Decorative Grasses for Under Fir Trees

Hardy to Minus 40 Degrees Fahrenheit

• Frost grass (Spodiopogon sibiricus), hardy in zones 4 to 9, grows best in lightly shaded sites with moist, well-draining soil. This 4-foot-tall grass has thin, upright foliage that turns red-to-maroone in autumn. Carnation grass (Carex firma) tolerates a variety of site conditions, including light shade and drought. This 2-foot-tall grass grows in dense clumps of fine, blue-green foliage. It is hardy in zones 4 to 9. Blue oats grass (Helictotrichor sempervirens), also hardy in zones 4 to 9, grows to 30 inches tall and thrives in partial shade and rich, moist, well-draining soil. Blue oats grass grows in dense clumps of blue-silver foliage.

Hardy to Minus 30 Degrees Fahrenheit

• Korean feather reed grass (Calamagrostis brachytricha), hardy in zones 5 to 9, grows best in partial shade. This warm-season grass grows in arching clumps of lustrous foliage that reach 30 inches tall. It prefers moist soil and produces red-purple inflorescences in fall that age to silver-gray. Purple moor grass (Molina caerulea) also grows well in partial shade and is hardy in zones 5 to 9. This 4-foot-tall grass tolerates poor soil and comes in a variety of cultivars, from the 18-inch-tall Variegated, which has yellow-white variegated foliage, and Moorhexe, which produces dark-purple inflorescences.

Hardy to Minus 20 Degrees Fahrenheit

• Japanese blood grass (Imperata cylindrica var. koenigii) is hardy in zones 6 to 9 and grows to 2 feet tall. It prefers moist soil, but is drought tolerant once its established. Japanese blood grass grows in upright clumps of fine green foliage with bright-red tips. Mexican feather grass (Nassella tenuissima), also hardy in zones 6 to 9, tolerates light shade and dry sites. This drought-tolerant grass grows to 2 feet tall and has fine, upright foliage.

Hardy to Minus 10 Degrees Fahrenheit

• Japanese sedge (Carex morrowii) grows best in shady, moist sites but tolerates drought once established. This stiff, white-and-green grass grows to 2 feet tall and is hardy in zones 7 to 9. Cultivars include Gold Band, which has yellow stripes, and Evergold, which has narrow foliage. Tenjiku sedge (C. phyllocephala) also grows well in moist soil and shaded exposures. This 2-foot-tall grass has upright, thick fronds and is hardy in zones 7 to 9. Cultivars include Sparkler, which has dark-green and white-striped foliage.