Before the North American prairies were settled by Europeans, the landscape was characterized by tall grasses. There were four species that dominated: Indiangrass (Sorghastrum nutans), switchgrass (virgatum), little bluestem (Schizachyrium scoparium), and big bluestem (Andropogon gerardii).
The Lady Bird Johnson Wildflower Center calls big bluestem the “star component” of the four tallgrass species. Big bluestem certainly looks striking. It can reach heights of up to 3 m and has unique flower/seed heads. The grass had an important role in the region’s ecosystem. It supported a range of wildlife, including songbirds, prairie chickens, white-tailed deer, bison, and butterfly larvae. It also provided fuel for prairie fires, which were actually crucial to the grass’ propagation.
Recognizing Big Bluestem
This tallgrass is quite distinctive in appearance. The culms (hollow stems) can grow up to 3 m in height and, true to its name, are often blue or purplish in colour. Most leaf blades are located on the bottom of the culms, becoming sparse further up the stem. Longer blades–up to 60 cm long–are clustered at the bottom of the culms, while shorter blades appear higher up the stem. The leaves are flat and rough on the top surface but smooth below. Leaves change colour seasonally, from light yellowish-green to blue-green to burgundy.
Each culm is topped by upright racemes. There may be 2-6 racemes but there are usually three, so that it resembles a turkey’s foot. (Another common name for Andropogon gerardii is turkeyfoot grass.) The racemes host tiny purplish flowers from July through October.
This tallgrass often grows in bunches or clumps.
Native to North America, big bluestem grows freely in all but the most westernmost provinces and states. It is hardy in Zones 4 to 9. As stated by the United States Department of Agriculture, big bluestem “is found in open woods, prairies, meadows, along riverbanks, and roadsides. It is especially abundant in lowland prairies, overflow sites, and sandy areas.”
Growing Big Bluestem
The United States Department of Agriculture (USDA) cautions that big bluestem “is invasive in some regions or habitats and may displace desirable vegetation if not properly managed.” The USDA advises that you consult with local agricultural agencies before planting this species.
Big bluestem, with its amazing height, is a stunner in home gardens. But the tallgrass is also a workhorse. It is often used for prairie restoration/reclamation, highway revegetation, stabilizing soil erosion, and protecting against wind erosion.
The tallgrass is easily grown from seed. Collect seeds from existing plants in September and October. Dry the seeds in paper bags for at least 2 to 4 weeks. Once dried, they can be stored for up to 7 months. In late winter or early spring, either sow seeds directly outdoors into soil or start indoors in seed trays. The soil needs to be kept most in order for seeds to sprout.
Planting in full sun and loamy soils will help big bluestem thrive. It requires regular moisture in its first year. But once established, it will adapt to its microclimate. Because it evolved as a prairie grass, big bluestem is tolerant of prairie-like conditions including drought and low nutrient levels in the soil. The U. S. Forest Service points out that fertilizing is actually not recommended. Fertilizers encourage the growth of competing weeds, choking out big bluestem.
Where possible, controlled burns can help native grasses like big bluestem spread. Burning clears the area of competing vegetation, giving big bluestem the space it needs to increase.
Big Bluestem and Butterflies
Dr. John Hilty points out on the Illinois Wildflowers website that big bluestem is a food source for several different species of skipper butterflies:
- Delaware Skipper (Atrytone logan)
- According to the Canadian Biodiversity Information Facility website, these yellow-orange butterflies can be found throughout central and eastern United States. Although they are “uncommon to rare” in Canada, they can be found in the southern regions of the prairie provinces, southern Ontario, and in one location in Quebec (Philipsburg).
- Dusted Skipper (Atrytonopsis hianna)
- These butterflies are brownish-grey with white spots. The Butterflies and Moths of North America website states that their preferred habitat includes grasslands, prairies, barrens, and old fields. This species ranges from central to eastern U.S.A., and predominates in the southern states. It has a very limited habitat in Canada, staying near the international border in southwestern Ontario, southern Manitoba, and southeastern Saskatchewan.
- Leonard’s Skipper (Hesperia leonardus)
- The Butterflies and Moths of North American website describes this species as red-orange with black borders on the top of the wings. The undersides of their wings are brick red with white-ish spots. Leonard’s skippers can be found in the northern U. S. A. from North Dakota to Maine. Its range in Canada is similar: it can be found in southern Canada from southeastern Saskatchewan to Nova Scotia.
- Cobweb Skipper (Hesperia metea)
- As described by the Mass Audubon website, cobweb skippers have brownish wings with an “elaborate underside pattern consisting of large whitish to yellowish spots connected by a cobwebby like tracery of whitish veins.” These butterflies are found in the eastern United States, from Minnesota south through Texas and extending to the eastern coast. It does not range into Canada.
- Ottoe Skipper (Hesperia ottoe)
- The Butterflies and Moths of North America website explains that these butterflies have brownish-orange colouring on the upperside of their wings and yellow-orange colouring on the underside. They primarily range in the central U. S. A., but have been found as far north as southern Manitoba and as far south as northern Texas.
- Indian Skipper(Hesperia sassacus)
- The Canadian Biodiversity Information Facility explains that these skippers have wings that are pale orange on the upper side and yellowish-orange on the underside. The upper side also has wide black borders. Like cobweb skippers, Indian skippers range throughout the northeastern United States and southeastern Canada.
- Byssus Skipper (Problema byssus)
- According to the Xerces Society website, byssus skippers are predominantly bright yellow-orange on both the upper sides and undersides of their wings. They also have striking black borders on the upper sides. These butterflies fly from Wisconsin down to Florida and eastward towards the coast in the United States. However, it is quite rare and is considered a “threatened” species in Iowa.
Big bluestem is an attractive grass for a home garden. Its height makes it particularly stunning in back borders. While it does actually flower, its nectar won’t attract as many butterflies as its foliage. Several different species of skipper butterflies seek out big bluestem as a food source for their larvae. If you’re creating a butterfly garden, why not plant some big bluestem both for visual interest and to support local butterfly populations?
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