Plant Profile: Karl Foerster grass

Karl Foerster grass as an informal screening plant.

Karl Foerster grass as an informal screening plant.

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.

Even in his 90s, Karl Foerster enjoyed time in his garden. (1967 photo)

Even in his 90s, Karl Foerster enjoyed time in his garden. (1967 photo)

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.

Hoar frost clings to the seed heads of Karl Foerster grass.

Hoar frost clings to the seed heads of Karl Foerster grass.

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.

 

7 Comments

  1. Cindy Marso on August 25, 2016 at 8:51 am

    My Karl Forester has what looks to be some kind of blight or fungus. The leaves have rust colored like lines on it. I looked up diseases and the miscantus blight best matched what is going on with mine. Now what?

  2. Mary Lahr Schier on August 26, 2016 at 11:11 am

    And, a bit more info from the National Gardening Association:

    ‘Karl Foerster’ is usually free of serious disease or insect problems although a foliar rust disease may appear in particularly wet summers and in situations with poor air circulation. Browsing deer don’t bother it. Little maintenance is required except to cut back the stems to about 6 inches in late winter or early spring. In areas with mild winters the foliage may remain evergreen.

  3. Chrs on July 4, 2018 at 2:32 am

    I have planted Karl forester grass in a very Sandy soil and they don’t appear to be growing. how fast do they grow maybe I am being anxious it had been abouta month and I can’t really see any growth they were about 14″ high and are the same

    • Mary Lahr Schier on July 4, 2018 at 3:06 pm

      Most perennials do not grow much their first year. I planted some Karl Foerster grass in very poor soil (somewhat sandy) between my patio and my neighbor’s patio. The first year it sat there, last year, it grew a bit taller but not what I had hoped for. This year, it is a full 5 feet tall and very lush. The old saying, first year sleep, second year creep, third year leap is true for many perennials. Good luck!

  4. gina sanchez on May 15, 2019 at 1:46 am

    I got some transplants of Karl forester grass from a construction site(they were going to throw them away) when I got them the root ball was still moist, but the were a little wilted, I planted them in my yard and have been watering them but they look dead. Does it take a year or two for them to come back from the shock?

    • Mary Lahr Schier on May 15, 2019 at 3:10 am

      Where are you located? In the North, Karl Forster is just coming out of dormancy now. Don’t over-do the water. Ornamental grasses can usually take a bit of dryness. Good luck!

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