Settlers nicknamed the prairie ‘The Great American Desert’ or ‘The Inland Sea’. They regarded it as something to be tamed, and indeed it came to be so: more than 95% of what was once prairie is now farmland. The steel plough invented by John Deere finally allowed the tough, deep roots of the grasses to be cut through and so the rich soil could be tilled and planted with crops. The small areas of prairie which remain today are microcosms of the vast prairies which once existed.
At least half of the plants that grow in a natural prairie are grasses, and in a tallgrass prairie the grasses are usually (but not always) tall. The two grasses which dominate in a tallgrass prairie are Big Bluestem and Indiangrass.
Big Bluestem is a generally dominant species but can in fact be so dominant that it forms a dense sod and thereby excludes other plants altogether. Such a prairie might then be called a Bluestem Prairie. Big Bluestem also grows in clumps, and in its habitat it is usually the tallest grass, reaching heights of nine or ten feet. Its name derives from the fact that its stiff, rounded stems are blue-green in colour. However in autumn, the stems and leaves turn an attractive burgundy red. Like most prairie grasses, Big Bluestem flowers in late summer. Its seedheads are branched like the feet of a bird, with typically three long spikes.
Indiangrass grows almost as tall as Big Bluestem and the two are often found together. Its stems are lighter and in fact even bluer. It doesn’t form sods in the same way as Big Bluestem, but grows in clumps. Both grasses flower at the same time and it is in this season that they are most distinct one from another because Indiangrass has striking yellow anthers. While Big Bluestem turns red in autumn, Indiangrass turns a bronze colour.
Two more types of grass make up the ‘Big Four’ grasses of the tallgrass prairie ecosystem. The first is Switchgrass which ‘only’ grows to about four to six feet in height. It tends to form sod rather than clumping. Its leaves are broader than those of the tall grasses it accompanies and its flowerheads are very slender and multi-branched with tiny, delicate flowers.
The other member of the ‘Big Four’ is Little Bluestem. It used to be thought of as being closely related to Big Bluestem, but it’s now considered to belong to a different genus. It has narrow leaves and forms sea-green or bluish clumps which turn to a bright coppery orange in autumn. It grows only to about four feet but is a very vigorous grass that can be found in both tallgrass and shortgrass prairies. Its seed spikes aren’t at all conspicuous.
There are many more varieties of grass – in fact seventy have been identified. However the four described above are the most characteristic and conspicuous in tallgrass prairies. Beautiful as they are in themselves, the grasses in original and restored prairies grow alongside myriad wildflowers. To those who love empty spaces and feelings of freedom, prairies are one of the most ideal environments.