Feather reed grass (Calamagrostis x acutiflora) is a popular ornamental grass used in landscape designs worldwide. Its strong vertical structure and seasonal plumes make it an attractive plant for both large fields and small garden spaces. This grass is a perennial, meaning it returns reliably year after year without replanting. It is valued for its low maintenance requirements and ability to provide visual interest across all four seasons.
Defining Feather Reed Grass as a Perennial
A perennial plant lives for more than two years, surviving winter dormancy to resume growth in the spring. Feather reed grass (Calamagrostis x acutiflora) fits this definition, as its root system remains alive underground even after the foliage dies back. It is a cool-season grass, meaning it begins its most active growth relatively early in the spring when temperatures are still cool.
This grass thrives across a broad range of climates, performing best in USDA Hardiness Zones 4 through 9. In these zones, the plant reliably returns from its crown annually, contrasting with annual grasses that complete their life cycle in a single growing season. While the green foliage turns a golden tan in cold weather, the roots withstand freezing temperatures.
Essential Seasonal Maintenance
Since feather reed grass is a perennial, care involves managing the old growth that accumulates during dormancy. The primary maintenance task is cutting back the previous season’s growth in late winter or very early spring. This pruning must be completed before new green shoots emerge from the base, as cutting fresh growth can leave unsightly marks. Gardeners typically shear the entire clump down to about 4 to 6 inches above the soil line using shears or a hedge trimmer.
Dividing the clumps every three to five years is important to maintain vigor and prevent the center from dying out. Division should be performed in early spring or early fall when the plant is actively growing. This process involves digging up the entire root ball and splitting it into smaller, healthy sections. Once established, the grass requires minimal intervention regarding water and nutrients, proving drought-tolerant and rarely needing fertilization.
Growth Habits and Appearance
Feather reed grass is known for its distinct, upright growth habit, providing a strong vertical accent in the landscape. It grows as a clumping grass (caespitose), meaning the plant forms dense, individual bunches. This clumping nature ensures it is non-invasive, as it does not spread aggressively through running rhizomes. The tight root ball expands slowly over time, which is why periodic division is needed.
The most recognized cultivar is ‘Karl Foerster,’ named the Perennial Plant of the Year in 2001. This variety is prized for its early-season blooms and striking plumes that emerge in early summer. The flower spikes initially appear as airy, rosy-pink or purplish-green inflorescences, transitioning quickly to a slender, golden-tan color. These stiff stems remain upright, holding their color through the fall and winter, offering a straw-colored texture to the dormant garden.