Salient Warm Season Grasses of the Shortleaf Pine-Oak-Hickory Woodland Groundcover

Little bluestem (Schizachyrium scoparium) is the dominant “matrix” grass of our shortleaf pine-oak-hickory woodland grassland just as it is with the vast majority of all tallgrass prairie groundcovers whether in a prairie or a woodland or a savannah.

Little bluestem is a warm season grass. Grasses are divided into cool season grasses that bloom and go to seed in the spring, and the warm season grasses that bloom and go to seed in fall; and some grasses are both.

Little bluestem (Schizachyrium scoparium)

However it’s the warm season grasses that play the dominant role in sustaining the balance of our ecosystem because they form the greatest bulk of combustible biomass needed to sustain the hot fires required in a grassland ecosystem. And it is those hot fires that are what’s needed to kill shrub species and other non-prairie species that might otherwise overtake and smother the ecosystem. Plus those hot fires induce bloom and seed production of both grasses and forbs (the wildflowers). Remember: hot fires are what sustain prairie grassland groundcovers.

So, in addition to Little bluestem, I’ll go over some of our salient warm season grasses here and in the next one or two posts.

All the salient warm season grasses, including Little bluestem, are bunch grasses. Bunch grasses grow in a bunch or clump and usually have roots that extend deep into the soil (up to six feet or more), thus providing these grasses with a hardy resistance to drought conditions. They are usually perennials (living year after year), and they provide excellent habitat and food for insects, mammals, birds, spiders, reptiles, and fungi (such as mycorrhiza that improve soil chemistry and provide nutrients to trees, grasses and forbs).  

One good example regarding quality habitat pertains to quail. Baby quail cannot walk or run well on carpet grasses to escape predators but they do very well in bunch grass habitats where they can quickly scoot on the ground around the clumps of bunch grass that provide excellent cover for hiding from predators.

Arrowfeather threeawn (Aristida purpurascens)

Another important grass is Arrowfeather threeawn (Aristida purpurascens). The genus Aristida encompasses the threeawn grasses. A grass awn is a little elongate “tail-like” structure attached to the seed head that has a mechanical function. According to the level of humidity the awn will coil and uncoil a bit moving the seed head forward, which increases the chance of bringing it in contact with the ground thus providing a greater opportunity of germination.  As the name “threeawn” implies, the genus Aristida has seed with three awns. Native to central and eastern North America, Arrowfeather threeawn is an example of another, smaller, perennial warm season bunch grass. Interestingly, the leaves at the plant bases become curly with age, a good field mark for its identification.

Splitbeard bluestem (Andropogon ternarius)

Last for this post is Splitbeard bluestem (Andropogon ternarius), a larger perennial bunch grass the size of Little bluestem. It is one of our most beautiful grasses during the fall when it has fully developed inflorescences (the bloom and seed heads) that can be seen in the picture. Splitbeard bluestem grows in the southcentral and southeastern portion of North America.

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Conservationist and retired medical doctor (pathology), Johnny Armstrong and his wife Karen and Opal (k-nine) live within a Nature Conservancy protected old-growth forest and woodland near Ruston, Louisiana. Shadowshine is his first novel..