Ornamental grasses have become increasingly popular in home landscape use. Ornamental grasses are generally low maintenance. Once established, most only need periodic combing, and sometimes, depending on the variety, an annual cut-back. General advice often states to cut them back in the fall, but here, where our winters are mild, many can provide texture, contrast and color in the winter garden, so I often leave the chore until early spring.
For grasses that are to be cut back hard, it’s easiest to wrap the whole clump with a piece of twine—some suggest masking tape—and then cut below that with well-sharpened shears. An old web or leather belt works great and is re-usable. That way the whole bundle of grass comes away clean without leaving a mess of stalks. Larger and tougher grasses may take a hedge trimmer, or even a small chainsaw. Muhlenbergia capillaries (pink Muhly grass) should also be sheared fairly low in early spring.
I love blue grasses. Festuca glauca (blue fescue) and Helictotrichon sempervirens (blue oat grass) are great performers, and don’t need to be cut back very often, but should be glove-combed out periodically to keep them looking good. A great fescue that I recently discovered is Festuca mairie (Atlas Fescue) and it gets treated the same way.
Calamagrostis x acutiflora ‘Karl Foerster’ looks lovely with its tall tan seed heads through the winter, so it gets cut back to 3-4 inches in February or March. Miscanthus sinensis (maiden grass) gets cut to around the same height then too, as does the Nasella tenuisima (Mexican feather grass). These latter re-seeds easily, so watch out for it to move into areas of the garden where it’s not wanted.
Pennisetum orientale ‘Tall Tails’ (oriental fountain grass) is another favorite – it’s similar to the more common P. orientale, but stands 4-5’ and works well in a tall perennial border. Cut it back before the new growth starts to appear, but after the cold weather is over—again, February or so. Cut back to about 3-4 inches above the crown of the plant. For Sesleria autumnalis, cut the clumps back in the spring to encourage new growth and to maintain good form and habit.