“A child said, what is the grass? Fetching it to me with full hands; how could I answer the child?. . . .I do not know what it is any more than he. I guess it must be the flag of my disposition, out of hopeful green stuff woven.”
–Walt Whitman, Leaves of Grass
Rain, rain, rain. We’ve had rain on several days the past few months but the Earth is still thirsty! The National Climatic Data Center (NCDC) released September through December’s Palmer Z drought index numbers and 52% of the upper Midwest, Plains, and Western half of the United States are still experiencing drought conditions. Despite the lack of moisture this season, Little bluestem, Schizachyrium scoparium, a native perennial bunchgrass, thrived.
A plant’s metabolism is partially responsible for its survival during extreme weather conditions. Perennial grasses can be classified as either C3 or C4 plants. Classification as a C3 or C4 plant is determined by the metabolic or biochemical pathway the plant uses to capture carbon dioxide during photosynthesis. While the C3 pathway is present in all grass species, the additional C4 pathway evolved in species adapting to very wet or dry habitats.
The C3 and C4 metabolic pathways are very different from one another. Each pathway is associated with a plant’s growing requirements. Little bluestem is a warm season, sun-loving, short grass species with preference for mesic to dry growing conditions and a C4 metabolism. Much like the weather of 2012, extremely dry growing conditions were experienced during the Great Drought of the 1930s. In 1932, Weaver and Fitzpatrick noted that Schizachyrium scoparium was more drought tolerant than some other prairie grass species found in the plains of North America. More recently, Hake conducted physiological field studies confirming the species-specific drought tolerance of Little bluestem.
Global climate change has brought about conditions of drought, high temperatures, and increased levels of nitrogen and carbon dioxide providing C4 plants, like Little bluestem, with a distinct advantage over those possessing the C3 metabolic pathway. In spite of its toughness, Little bluestem’s clumped foliage is delicate and beautiful. Slender, erect, blue-green stems or culms appear in August and reach 2-3 ft. tall by September. The alternate, 1/4 inch wide and 10 in. long leaves are located on the lower part of each culm. In late fall, the culms and leaves turn a rusty-red color and are topped with white tufts of shining seeds.
The tufts of shining white seeds or spikelets form on 1 1/4 to 3 in. stalks or racemes the end of each culm. Several pairs of spikelets occur on opposite sides of the raceme’s central stem. Between the central stem of each spikelet, long white hairs are produced. Two pairs of spikelets are produced; a sessile, fertile spikelet and a sterile spikelet. The fertile spikelet is about 1/4 in. in length and the sterile spikelet is 1/8 in. in length. Each fertile spikelet produces a single elongated grain. The floret’s anthers are brown to reddish brown and the stigmas are pale purple in color.
Below the ground, Little bluestem possesses a dense and fibrous root system. Reaching 5 to 8 ft. in depth, the predominantly vertical roots provide both erosion control and protection from drought. Little bluestem has a symbiotic relationship with the fungus, arbuscular mycorrhizae, which improves its supply of water and nutrients. In return, Little bluestem transfers 20% of its plant fixed carbon to the fungus. In light of its erosion control and drought tolerance characteristics, Little bluestem is often used in conjunction with other C4 grasses for prairie restorations and revegetation of abandoned cultivated lands.
An adaptable grass, Little bluestem thrives a wide range of soils and tolerates harsh growing conditions but prefers neutral to slightly basic sites with deep, shallow, sandy, fine-textured and rocky soils that are characteristically medium to dry, well-drained, and infertile. The plant thrives in full sun but will tolerate light shade. Little bluestem readily seeds itself. Caution should be exercised when planting it in small areas with ideal growing conditions since reseeding can result in Little bluestem becoming the dominate species in the garden.
Growing conditions, including climate and soil type, have an effect on the geographical distribution of a grass. The Little bluestem range extends throughout all of the lower 48 states except Nevada and are most prominent in the Great Plains and open canopy of the eastern United States. More state specific plant locations can be found on the USDA’s Schizachyrium scoparium distribution map. Common throughout Illinois, Little bluestem’s native habitats include hill, gravel, sand, loam, and clay prairies, scrubby barrens, rocky slopes of thinly wooded bluffs, sandy savannas, hilltop glades, dunes, gravel railroad right of ways, and abandoned fields.
Little bluestem’s vast geographic distribution also plays an important role in various ecosystems throughout North America. It is the food source and/or cover for songbirds, upland game birds, ground birds, mammals, and insects. During the winter in Illinois, Little bluestem seeds are favored by the Field Sparrow, Tree Sparrow, Slate-Colored Junco, and other small songbirds. Other Illinois avian inhabitants such as the Prairie Chicken, Sharp Tailed Grouse and the quail use the foliage of Little bluestem as nesting material or cover. The foliage of Little bluestem found in Illinois is quite palatable to bison, cattle, White Tailed Deer, and other mammalian herbivores. Ecologists have identified an invaluable relationship between the Little bluestem and insects. Insects are abundant in prairies, providing an ample food source for others higher up in the food chain, birds in particular. Little bluestem’s leaves are the food source for butterflies, skippers, grasshoppers, spittlebugs, leafhoppers, thrips, and beetles. In Illinois, the native grass provides nutrients for Atrytonopsis hianna, Hesperia leonardus, Hesperia metea, Hesperia ottoe, Hesperia sassacus, Nastra lherminier, Polites origenes, numerous grasshopper species, Prosapia ignipectus, Flexamia delongi, Laevicephalus unicoloratus, Illinothrips rossi, and Aniostena nigrita.
Commonly found in prairies across North America, the ornamental, native bunchgrass, Little bluestem, plays an important role in ecological restorations. Not only does it provide a food source for many native fauna species, it is also a drought resistant native grass, particularly suited for survival in our changing environment. Weather extremes are the new norm throughout the world. This phenomena seems to be born out in an unseasonably warm and dry year in Illinois. Our winter this year has also been warm and dry. In fact, the 2012 National Oceanic and Atmospheric Administration National Climatic Data Center recently stated that the recent year’s weather “…is consistent with what we would expect in a warming world.” Clearly environmental adaptations are necessary for ecosystems to remain sustainable in a warming world. This report will require all gardeners, even native gardeners, and prairie restorationists will need to adapt their plant selections to accommodate the climate change. I plan to do my part to help create a more sustainable landscape by planting a few more Little bluestems in my garden!
Related articles
- Plants can go thirsty but only for so long (futurity.org)
- U.S. drought pushing plants to their limit (upi.com)
Resources:
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“Schizachyrium scoparium (Mich.) Nash.” Lady Bird Johnson Wildflower Center. University Texas at Austin. N.D. Web. 12 Sep. 2012.
Hake, D. R. etal.,”Water stress of tallgrass prairie plants in central Oklahoma.” J Range Management, Mar. 1984. Web. 2 Oct. 2012.
Hilty, John. “Little Bluestem.” Illinois Wildflowers. N.P. 2002. Web 10 Nov. 2012.
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” Plants Profile, Natural Resources Conservation Service, United States Department of Agriculture. 2002. Web. 1 Jun. 2012.
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Weaver, J. E. and Albertson, F. W., “Effects of the Great Drought on the Prairies of Iowa, Nebraska, and Kansas” Agronomy Faculty Publications. 1 Oct. 1936 Web. 1 Sept. 2012.
Weaver, J. E. and Fitzpatrick, T. J., “Ecology and relative importance of the dominants of the tallgrass prairie.” Botanical Gazette. 1 Apr. 1932 Web. 1 Oct. 2012.
“What are C3 and C4 native grass Species?” NSW Government, Department of Primary Industries: Agriculture. N.D. Web 1 Nov. 2012 .