Ornamental grasses are meant to grow and spread without requiring frequent trimming, like grass in the lawn, but they do require an annual clean-up to remove dead foliage. Flowers, seed heads and old blades that die must be cleared out to make room for new growth in spring. You can clear out the dead growth in late fall or early spring. Grasses that produce large, showy plumes, such as pampas grass (Cortaderia selloana), offer feathery texture to a bleak winter garden, so you might want to wait until spring to cut them.
1 Pull the living foliage back to gain access to the dead material within the ornamental grass. Have a helper hold the live foliage out of the way if the dead foliage is difficult to get to.
2 Grasp a bundle of dead growth in your hand and use hand shears or a sharp knife to cut through the dead grass blades. Cut about 6 inches above the ground or as short as 2 inches when dealing with low-growing ornamental grasses. Hold the bundle together while you cut so you can easily discard the dead grass without having to pick through the living foliage.
3 Gather another bundle of dead growth in your hand and cut it back to 6 inches. Repeat this process until you remove as much of the dead growth as possible.
4 Pick through the live foliage to find any remaining individual blades of dead growth and cut them back as you work your way to to opposite side of the plant. Add the dead plant material to a compost pile or a green materials waste bin.
Items you will need
- Hand shears
- Work gloves
- Protective clothing
- Twine (optional)
- If you don't have anyone to help you separate the live foliage from the dead growth, use twine to tie bundles of dead growth together. After tying up as much of the dead material as possible, go back through and cut the bundles. The twine keeps the bundles together for easy clean-up and disposal.
- Pampas grass grows in U.S. Department of Agriculture plant hardiness zones 7 through 11, but is considered invasive in some areas.
- The leaves of some ornamental grasses turn brown in fall and must be cut back entirely every year to within 2 to 10 inches of the ground, depending on the mature size. Some varieties of maiden grass (Miscanthus spp.), which grows in USDA zones 4 through 9, grow up to 12 feet tall and should be cut back to 6 to 10 inches. Japanese bloodgrass (Imperata cylindrica "Rubra"), which grows in USDA zones 5 through 9, grows only 1 1/2 feet tall, and should be cut back to within 2 inches of the ground.
- Wear long sleeves and gloves when working with ornamental grasses. Some grasses have spines along the edges or sharp blades that can cut your skin, while other grasses can cause skin irritation if you rub against them.
- North Coast Gardening: Ornamental Grasses: How to Prune Miscanthus, Stipa, and More
- University of Illinois Extension: Ornamental Grasses
- University of Rhode Island Landscape Horticulture Program: Ornamental Grasses
- Colorado State University Extension: Ornamental Grasses
- Sunset: Gorgeous Grasses
- University of Nebraska-Lincoln: Ornamental Grasses for Nebraska Landscapes
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