Perennial grasses such as Switch Grass (Panicum virgatum), Big Bluestem (Andropogon gerardii), and Indian Grass (Sorghastrum nutans) are native plants to the Middle Atlantic. Native grasses vary in height from two to eight feet, depending on the species and site. These plants are often called warm-season grasses because they break dormancy later than some perennials and grow strongly during the late spring and summer months. Many people find the grasses look best when they show amber and golden fall colors, and dried stalks during winter, long after other plants lose interest. In July, these grasses are in their glory, and starting to grow well.
The native grasses need little maintenance once established. It is best to cut native grasses once or twice each year. Another way they differ from typical lawns is that they grow deep root systems. These roots make the native grasses drought-tolerant and hardy. There is a native grass for any site. Some species prefer dry areas, others are shade-tolerant, and a few work best in wet, boggy areas.
Unlike the traditional lawn, native grasses provide habitat for birds throughout the year. That’s an important dividend for watching birds right outside your windows. The seeds and dried stalks of tall grasses serve as cover for overwintering insect larvae, butterfly caterpillars, spiders, and snakes. Larger, grassy meadows also provide good hunting ground for raptors searching for small mammals and insects. However, you can start a meadow area in just 100 or 200 square feet where you now have lawn. It is often best to begin on a sunny, perimeter area next to some mature trees, a pond, or other natural feature.
When spring comes, the tall grass is full of food sources for birds and holds abundant material for nests made by Eastern Meadowlarks, Sparrows, and Bobolinks, for example. In spring and early summer these grassy areas transition from serving primarily as cover to offering both shelter and food sources for arriving birds and new fledglings.
So, after you establish an area of warm season grasses, when should you mow? It generally takes two years for native grasses to establish good root systems and begin robust growth. Then, you should mow your native grass once or twice per year. Mowing in late June or early July is good for controlling the growth of non-native grasses without interfering with the seed forming on native grasses during mid-late summer. Mowing in March is also a good choice because it will not disturb breeding birds, and it encourages good Spring growth.
Birds need tall grasses for food, shelter, and to foster biodiversity that all native species rely on, but perhaps some of your human neighbors prefer to see neatly cut lawns. It helps create tolerance and support for your no-mow area when you educate teachers, students and neighbors about benefits of native grasses. Try to explain that these are native plants with important function in all four seasons of the year, and not just any old weed.