We highlighted Karl Foerster grass back in 2012 as one of our favorite plants for Minnesota, but let's sing the praises of this striking, easy care, four-season beauty once again.
Karl Foerster (Calamagrostis x acutiflora ‘Karl Foerster’) is a feather reed grass, an ornamental clump-forming grass that grows in USDA Zone 4 and southward. It is named for a German horticulturist and an early pioneer of lower maintenance gardening. Karl Foerster was born in Berlin in 1874 and lived and gardened until 1970! (More evidence of the health benefits of gardening!)
According to this interesting short biography, he was the father of the "new German style" garden, which emphasized plants that had beauty, resilience and endurance. In addition to his famous (some might say ubiquitous grass), he collected and bred delphiniums, white roses and was the first person to cultivate the very popular Rudbeckia fulgida var. sullivantii ‘Goldsturm’.
Because it is clump-forming, Karl Foerster grass does not spread. It stays put in a nice, slowly expanding clump. After seven to 10 years, you may want to divide it. The plant has basically no disease or pest problems and requires little in the way of fertilizer or even water. In the driest of years, Karl Foerster stands tall.
This grass grows 3 to 4 feet high and looks lovely in the back of a planting bed or even used as a low screen. I have several planted around my front yard patio. The plants supply just enough cover to sit on the patio without feeling exposed. They look wonderful grown in masses and are the perfect companion to many prairie plants.
Each year, the Karl Foerster grass begins with simple green blades. In late summer, golden flower heads form, which wave in the breeze. While you can cut it back in fall, I like the way the grass looks in winter, too. Hoar frost clings prettily to the seed heads and the plant stands tall through most (not all) of the winter. Some plants will lodge (fall over), but many stay tall until spring. I usually cut mine back to about 6 inches tall in late April.
For a plant that requires almost no care, you cannot go wrong with Karl Foerster grass.