Feather Reed Grass
Adapted from a Perennial Plant Association article

The Perennial Plant Association has named Calamagrostis x acutiflora 'Karl Foerster' as their Plant of the Year 2001. This highly acclaimed variety of Feather Reed Grass is one of the most versatile, attractive, and low maintenance ornamental grasses. 

The deep green, shiny foliage of this cool season grass appears in early spring and lasts until early winter. It forms an erect, narrow upright clump. Loose, feathery flower inflorescences appear in June. The tight green heads open to airy rosy-pink plumes that later changes to dark maroon, then to bronze, and finally to golden tan over a three- to four-week period. This color then lasts through the fall season. 

The growth habit is vertical with a tuft of foliage 2-3 feet tall and flower stems to 5 feet in height. The narrow, tight habit of this cultivar creates a clump only 1½ to 2 feet wide. In mild winters the foliage rosettes remain evergreen or may show some growth.

C. x acutiflora is reported to be a natural hybrid of C. epigejos and C. arundinacea that  was introduced to the nursery trade and general public in 1950 by Karl Foerster. According to Mr. Foerster, the source for the plant was the Hamburg Botanical Garden. It was imported into the United States from Denmark in 1964. It is almost identical to C. x acutiflora ‘Stricta’ (so identical that these plants are often confused by some nurseries) but ‘Karl Foerster’ does not self seed.

Propagation

This grass is best propagated by division in the fall or spring. Large clump division may be done in the fall with a good show of flowers the following spring. Smaller clumps will require a second growing season to fully develop a mature flowering effect.

Cultivation

This long-blooming and long-lived perennial grass grows best in full sun to partial shade and prefers well-drained, fertile soils with sufficient moisture, but will tolerate heavier clay soils and drier sites. Fertilization may be required to produce maximum height in infertile soils. It is usually free of serious disease or insect problems, although a foliar rust disease can occur in wet summers where there is poor air circulation. It will flop over if grown in shade.

Little maintenance is required except to cut back the stems to about 6 inches in late winter or early spring. Since it starts it’s growth early in spring, get out there early to cut back old growth before new growth begins. Sterility eliminates any chance of this cultivar becoming an invasive plant or create unwanted seedlings in the garden.

Landscape Uses
C. x acutiflora 'Karl Foerster' is excellent as a specimen plant, providing a vertical accent in the landscape or as a massed planting. The slightest breeze sets this grass in motion and the graceful movement is a highlight for any landscape. In heavy rain or wind the stems will dip and droop in all directions but return to vertical as soon as the storm passes. Put it in a spot where the afternoon sun will shine on the seedheads, making them appear almost golden  in color, for a dramatic effect. It is also useful in patio pot containers and will survive most winters without winter protection. A combination of Karl Foerster feather reed grass with various other perennials makes a dramatic effect in the landscape. Consider combinations with late summer and fall-blooming perennials blooming perennials such as Coreopsis, Echinacea, Liatris, and Rudbeckia.

This grass is also good for use in fresh or dried arrangements. Stems cut before the flowers mature will last for months in an arrangement, while maintaining the golden tan color.