Big Bluestem
Look out upon many Iowa ditches in the fall, and you are likely to spot tall grass tassels with a purplish hue. With a prominent seed head shaped like a turkey’s foot, this native species is commonly known as big bluestem. It is a keystone species of the prairie ecosystem that once spread all across Iowa.
Andropogon gerardii is a native, perennial, warm-season grass that grows to heights of 6-10 feet when protected from grazing. Large stands of bluestem used to feed enormous populations of prairie animals ranging from grasshoppers to bison.
The prairie ecosystem depends largely on big bluestem, the way our hardwood forests depend on oaks and hickories. In a very real way, we can’t have Henslow’s sparrows, prairie-chickens, regal fritillaries, grassland crayfish, Mead’s milkweed, prairie fringed orchids, and a host of other prairie-restricted species without big bluestem.
It grows in a wide range of soil types and can tolerate shallow depth, low pH, and low fertility. Big bluestem is drought-resistant and thrives in the heat and light of full sun. Its deep, fibrous root system helps stabilize the soil and is primarily responsible for its fire-resistance.
Despite its tall stature, only one-third of big bluestem is typically visible. A massive two-thirds of the plant lives below ground, extending 10-12 feet deep. These deep root systems reach water in dry conditions, access more nutrients, build and maintain healthy soil, and provide underground habitat for insects and microorganisms.
Fire actually stimulates big bluestem by clearing away the previous year’s growth and allowing more sunlight to reach the ground. This warms the soil faster in early springtime.
Big bluestem has relatively weak seedling vigor compared to weeds and cool-season grasses, which makes control of competition necessary to establish a self-sustaining stand. Yet once established, stands of bluestem require little maintenance and support a diverse collection of flora and fauna.
Big Bluestem
and the People
of the Prairie
To the Indigenous ancestors of Iowa, big bluestem was more than just a grass on the prairie—it was a trusted companion in daily life. The roots were brewed into medicine to ease stomach pains and draw excess water from the body, while the leaves could be steeped into soothing washes to calm fevers or blunt pain. Beyond its healing uses, the plant found its way into the rhythm of home and hearth. Strong stalks helped secure the poles of lodges, and in the cooking fire, damp bundles of grass were laid across hot stones to trap the steam. Families even turned to it when tending their fruit, spreading grass like a protective blanket—draped over ripening harvests or laid beneath as fruit dried in the sun.
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