When I was first introduced to the important native prairie grasses, I knew nothing about grasses and had no eye for distinguishing characteristics. Side-oats grama was one of the first ones I could recognize. The seeds (technically single-seeded fruits, achenes) hang suspended on a 6-9-inch stalk, different from all the other common prairie grasses. Then there was the mnemonic; I always said to myself, "Them's side-oats, gra'ma." Learning Bouteloua curtipendula was less easy, but there are several important species also in Bouteloua, the word has a nice rhythm to it, and curtipendula means "short-hanging" describing the seeds.
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| sideoats grama, Bouteloua curtipendula |
Sideoats grama is a native mid grass (grass family, Poaceae), growing 2-3 feet tall. It is a warm season grass with the C4 photosynthetic pathway, allowing it to conserve water and grow under dry conditions. The leaves are narrow and straight. It flowers in mid to late summer. The florets are light red purple with red-orange anthers hanging from them. In fall, sideoats grama can turn a handsome reddish shade.
This is a grass that is native all over North America except the Pacific Northwest and parts of New England (see BONAP map
link) and has been introduced beyond that area. Its native range extends to Argentina. As you might expect with that large a range, there is great variation and several subspecies are debated.
It was most common and important in the mid-continent prairies. One of the dominant grasses of the drier prairies, in times of drought it moved way eastward, replacing taller, less drought-tolerant grasses. In moister periods it could be found on dry or rocky slopes.
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| sideoats grama, Bouteloua curtipendula |
In the eastern U.S. it grows in extremely dry sites, for example slopes with shallow rocky soils. These sites are scattered over the Appalachian Mountains and it appears that they are increasingly isolated. The achenes of sideoats grama can only travel a few yards by wind and if cattle eat them, they are destroyed, thus it was a puzzle how they traveled up and down the Appalachian mountains. Laughlin did a series of experiments as to whether sideoats grama seeds could become lodged in animal fur and travel that way. Testing a variety of animal furs, the fur of bison and elk held the seeds longest. However, both animals have been extirpated from the Appalachians. Botanical records suggest that, in the Appalachians, sideoats grama numbers are down about 50% it the last 100 years, due to agriculture, development, and woody plant invasion. With suitable sites for seedlings few and far between and poor dispersal, sideoats grama is increasingly declining in the eastern part of its range.
West of the Appalachians, sideoats grama is growing well and, while not exactly weedy, easily colonizes disturbed sites like abandoned dry pastures. (Tho presumably not over long distances, since bison and elk are rare in the midwest and west too. It is a desirable range grass and is often planted in grassland restoration.) A tough native, it is drought, heat, and cold tolerant.
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| sideoats grama, Bouteloua curtipendula |
This photo is from the 1980s and the color of the film has distorted, but all that orange is sideoats grama in a native prairie in the Kansas Flint Hills. It can be very abundant without human help.
Hillside of sideoats grama,
Bouteloua curtipendulaThe genus Bouteloua honors two Spanish botanists, the brothers Claudius and Esteban Boutelou (1774-1842 and 1776-1813 respectively).
The leaves of sideoats grama are good forage for cattle and bison. The seeds are eaten by rodents, birds, and insects. The plant is the host for several species of skipper (genus
Hespera, Lepidoptera, moths and butterflies).
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| sideoats grama, Bouteloua curtipendula |
Kiowa warriors wore stalks of sideoats grama as an ornament if they had killed an enemy with a lance; note the resemblance to a feathered lance.
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| sideoats grama, Bouteloua curtipendula |
Last but certainly not least, sideoats grama is the state grass of Texas.
Comments and corrections welcome.
References
Clear Creek Chapter Texas Native Plant Society. 2022. Plant of the Week. Sideoats Grama. link (Accessed 5/12/23)
Lady Bird Johnson Wildflower Center. Sideoats grama, Bouteloua curtipendula link (Accessed 5/12/23)
Laughlin, D.C. 2003. Geographic distribution and dispersal mechanisms of Bouteloua curtipendula in the Appalachian Mountains. The American Midland Naturalist. 149(2), 268-281.https://doi.org/10.1674/0003-0031(2003)149[0268:GDADMB]2.0.CO;2 (Accessed 5/12/23)
Moerman, D. E. 1998. Native American Ethnobotany. BRIT Press, Fort Worth, Texas. link (Accessed 5/12/23)
Kathy Keeler, A Wandering Botanist
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