Ornamental grasses have become popular features in the landscape and garden. Their vertical growth and form, beautiful flower spikes, winter color, easy care make ornamental grasses both interesting and functional. One of the most attractive and versatile ornamental grasses is feather reed grass, Calamagrostis acutiflora 'Karl Foerster'. It can be used in many different landscape situations and always performs well. It is one of the most commonly available ornamental grasses on the commercial market.
Feather reed grass is a sterile hybrid between Calamagrostis arundinacea and C. epigeous. There is some confusion between C. acutiflora 'Karl Foerster' and another cultivar C. acutiflora 'Stricta'. 'Karl Forester' is sometimes listed as being a cultivar of Calamagrostis arundinacea rather than C. acutiflora. Some authorities have lumped the two together claiming the differences are minor and, generally, they seem to be sold as one and the same.
Feather reed grass is one of the longest "blooming" ornamental grasses, with airy purple tinted flowers starting in mid-June changing to tan-colored, erect seed heads by mid-August and remaining attractive over the winter. The tan seed spikes have a tight, wheat-like appearance. The 5 to 6 foot tall flower stems, borne above 30" foliage, flow gracefully in the lightest breeze and can bend to the ground during a rain only to quickly regain their strong vertical form.
A native of Europe, feather reed grass is a low maintenance perennial. It is tolerant of a wide range of cultural conditions, including dry, wet, or heavy soils, although it prefers moist, rich soil in full sun. Although it will tolerate partial shade, it may not flower as well and the normally erect stems may flop over. Feather reed grass is hardy from zones 5 - 9 and is one of the few cool season grasses that thrive in the heat of Iowa's summers. It also has no known pest problems.
The only attention required by feather reed grass is cutting the dead foliage back in early spring, before the new growth begins (usually in late March). Check the plants often in early spring because feather reed grass is one of the first ornamental grasses to emerge in the spring and it grows and develops quickly.
Feather reed grass is not aggressive and since it is sterile, it does not self-seed. It retains its clump form for years. Spring is the preferred time to divide the clumps, however, they can be divided in the fall. The plants should be planted two to three feet apart, depending on the intended landscape use.
Due to its many attributes, feather reed grass has multitudes of uses in the landscape. Because of its strong upright clump-forming habit, it is one of the best grasses for small gardens or tight spaces. Used as a specimen, it makes a stunning vertical accent. In groups, it creates a horizontal band of golden spikes that bend and sway in the wind. The strong flower stems are beautiful additions to fall arrangements.
This article originally appeared in the April 11, 1997 issue, p. 41.