Calamagrostis x acutiflora (Feather Reed Grass)
Calamagrostis x acutiflora, commonly called feather reed grass, is a dramatic ornamental grass useful in mass plantings or as a strong vertical accent in a perennial bed.
By far the most common and popular cultivar is 'Karl Foerster,’ considered by professional gardeners as one of the most versatile, attractive, and easy-care of the ornamental grasses.
- Arching, shiny green, 2-3 ft. foliage tussocks form in early spring.
- Soft mounds give rise to a central clump of flower stems in summer that rise 5-6 ft., topped with feathery flower heads in striking pink or pale plum.
- As seed heads mature, they become quite narrow and turn a golden tan.
- Tussocks of arching grasses slowly expand. Ultimate size depends on soil fertility, moisture, and whether clumps are divided.
- Despite its narrow profile, this grass sways gracefully in a light breeze.
- ‘Karl Foerster’ is frequently planted in a row along a fence or roadway, but single specimens stand out against lower, long-blooming perennials, particularly late-summer and fall-blooming species.
‘Karl Foerster’ is a deciduous grass that looks best when clumps are cut back to 2-4 in. above ground in very late autumn or winter before winds scatter dried foliage.
- ‘Karl Foerster’ can be propagated easily by division in late fall or early spring.
- Seeds are sterile and will not self-sow to become an invasive problem.
- In hot situations with less than optimum moisture, summer heat may cause grass to dry prematurely and enter summer dormancy.
- ‘Karl Foerster’ tolerates clay and part shade, but does best in full sun in moist, but well-drained, fertile soil.
Other Calamagrostis Grasses
Two variegated Calamagrostis x acutiflora cultivars are similar to ‘Karl Foerster’ and just as garden worthy. Both are variegated, more compact than ‘Karl Foerster,’ and develop a more delicate texture.
- Both are best in partial shade in hot inland areas.
- ‘Avalanche' appears somewhat more delicate with wide, white leaf variegation.
- ‘Overdam’ shows more green than white in its leaf stripe.
- The Cape Mendocino reedgrass, Calamagrostis foliosa native to the California North Coast, is strikingly different from the hybrid Calamagrostis x acutiflora.
- This cool-season species is far more drought-tolerant but benefits from moderate to occasional irrigation.
- It forms a low, loose mound of bluish green grass 1 ft. high by 2 ft. across.
- Fawn-colored seed stalks arch gracefully over foliage. Ripe seed heads shatter in maturity.
- This grass does not require shearing; dried leaves may be raked out. Grasses are best replaced after 5-7 years.