AMES, Iowa – Fall brings with it beautiful colors across the state. Most identify trees with those spectacular vistas, but ornamental grasses also can provide great color for landscapes. Which grasses are best for fall foliage, and which are best equipped to deal with winter’s cold conditions?
Iowa State University Extension and Outreach horticulturists can help answer questions about ornamental grasses and how to handle them during the winter. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
Are there ornamental grasses with colorful fall foliage?
Several ornamental grasses develop good fall color. Switchgrass (Panicum spp.) cultivars with colorful fall foliage include ‘Rehbraun’ (reddish brown), ‘Rotstrahlbusch’ (burgundy red), and ‘Prairie Fire’ (wine red). In fall, Miscanthus cultivars ‘Purpurascens’ and ‘November Sunset’ have orange-red and golden orange foliage respectively.
Little bluestem (Schizachyrium scoparium) has yellow to burnt orange fall color. The fall color of little bluestem cultivar ‘Blaze’ is orange to reddish purple, while ‘Blue Heaven’ develops a burgundy red color in autumn. ‘Red October,’ a cultivar of big bluestem (Andropogon gerardii), has burgundy red foliage in fall. The fall foliage of ‘Cordoba’ purple moor grass (Molinia caerulea ssp. arundinacea) is golden yellow. ‘Tara’ prairie dropseed (Sporobolus heterolepis) develops an orange-red fall color.
When should I cut back my ornamental grasses?
Many ornamental grasses provide color, sound, and movement to the winter landscape. Because of these winter features, cut back ornamental grasses in April in Iowa. Cut back the grasses to within 2 to 4 inches of the ground with a hand shears, lopping shears or hedge trimmer.
I planted fountain grass in the garden this spring. Will it survive the winter?
There are several species of fountain grass. Perennial fountain grass (Pennisetum alopecuroides) is a perennial grass. It is hardy in much of Iowa. Annual fountain grass (Pennisetum setaceum) is a widely grown annual grass. The most popular annual cultivars are those with reddish purple foliage, such as ‘Rubrum.’ Annual fountain grass will not survive the winter in Iowa.
The central portions of several of my ornamental grasses are dead. Why?
The centers of ornamental grasses often die as the plants get older. When this occurs, it’s a good time to dig and divide the grasses. When the grasses begin to grow in spring, dig up entire clumps, cut out and discard the dead center portions of each clump, cut the outer portions into sections and replant.