Appreciating Native Grasslands
Appreciating Native Grasslands
Habitat Enhancing Land Management
Part 1 — Getting to Know Them
“Next in importance to the divine profusion of water, light, and air, those three physical facts which render existence possible, may be reckoned the universal beneficence of grass.” — John James Ingalls
Christine Middleton
Grass. What comes to mind when you hear the word? A bright green expanse of well watered, continuously fertilized, frequently mown lawn? Or vast meadows filled with tall grasses mixed with wildflowers gently swaying in the breeze?
The first is a monoculture, where only one species of non-native grass is allowed to survive. It is expensive and labor intensive to maintain and devoid of life—except for the occasional deer who comes to snack on the “weeds” that escaped your notice.
The other is a diverse landscape supporting a wide variety of insects, birds, and other wildlife. It requires much less human assistance to thrive. It is Nature at its best.
Besides providing critical wildlife habitat, native grasslands do a lot more! When it rains, the deep roots of native grasses create pathways directing water into our aquifers. In times of too much rain, tall grasses slow the flow of floodwater and protect the banks of our creeks and rivers. In the uplands, grasses hold soil in place against the erosive impact of water. And, as the grasses die down every year, the material left behind builds soil. Like trees, native grasses absorb carbon, albeit on a small scale. But then again, if we mow frequently, the process releases lots of carbon!
This experimental plot at the Lady Bird Johnson Wildflower Center is one of many being used to study the impact of different grassland treatment regimes.
Grasslands are defined as places where 50% to 90% of the vegetation is grass. But not just one kind of grass—rather, a diversity of grass species. And grasslands aren’t just grasses, but include lots of wildflowers we love. And there are also some trees and shrubs. The proportion of trees and shrubs to grass determines the difference between two other terms for grassland that are sometimes incorrectly used interchangeably: prairie and grassland savanna.
A prairie implies a grassland that includes very few trees or shrubs. A small portion of eastern Hays County is part of the Blackland Prairie ecoregion. That region stretches from just south of the Red River on the Texas/Oklahoma border and generally follows the east side of IH35 all the way to San Antonio. Prairies are prime agricultural land, meaning, unfortunately, that not much of the original tallgrass prairie remains.
Unlike prairies, grassland savannas are an expanse of grasses and forbs, broken up by a mosaic of small thickets. Most of Hays County is in the Edwards Plateau ecoregion. Before European settlement, much of our county was a mix of grassland savannas and woodlands. Many factors, including overgrazing, erosion, and the absence of fire, have dramatically changed vegetation patterns. Over time, more and more of our grassland areas have become woodlands.
To restore the balance between wooded and grassland areas, land stewards need to understand native grasses—how they grow, why they are growing where they are, and how to manage them in ways beneficial to both ourselves and our wild friends.
Grasses have flowers!
So what is grass anyway? Vegetation we refer to as grass belongs to the third largest family of flowering plants, the Poaceae. And, yes, grasses have flowers! You may not notice the flowers because they are often inconspicuous. Sometimes you need a magnifying glass to really see them. Grass flowers don’t produce nectar. But they do contain pollen, which is why you might see a bee visiting a grassy meadow. Native grasses also provide ground-nesting bumblebee queens’ protected sites where they can overwinter.
But wait! You have surely noticed butterflies landing on grass blades. What’s going on if there is no nectar to be had? The butterfly may simply be searching for a droplet of water that has become trapped in a crevice on the seed head. Or, if it is the female of a species for which that grass is the host, she is probably depositing eggs. Grasses in the genera Panicum (e.g., Switchgrass), Paspalum (e.g., Hairyseed paspalum), Andropogon (e.g., Bushy bluestem), and Bouteloua (e.g., Sideoats grama and Buffalograss) are all larval hosts for a variety of butterflies and moths.
Other insects like this scorpionfly like grass too. Photo: Mary O’Hara
Grass attracts/protects our wild friends!
Grass is food for wildlife. Lots of birds, including finches, chickadees, titmice, and cardinals, as well as winter migrants, such as cedar waxwings and orioles, eat seeds produced by our native grasses. While we delight in seeing birds at our feeders, like many of us, they prefer food from the freshest source possible. According the David Allen Sibley in his book What It’s Like to Be a Bird: What Birds Are Doing and Why, “Even chickadees, among the most dedicated bird feeder customers, get at least 50 percent of their food in the wild.” So why not think of your property as a giant bird feeder and the food you fill it with as simply supplemental nutrition?
Wild turkeys require grassland habitats where they can forage for food and utilize grass for cover and nesting. Photo: Mike Davis
Some species of birds, such as geese and ducks, actually eat the grass itself. Small mammals such as rabbits and skunks include grass among the wide range of things they like to nibble on. Deer eat little grass and then only the tender shoots of newly sprouted grass. That’s because, unlike cattle and other grazing animals, deer cannot efficiently digest mature grass. At one time, that huge grazer who roamed Central Texas, the American bison, consumed lots of grass. But—unlike our cattle and sheep—the bison kept moving on, enabling the grasslands to recover before the bison returned months or even years later. So grass has evolved to withstand some level of nibbling.
Photo: Garit Stewart
Grass provides shelter for wildlife. In addition to forage, tall native grasses provide cover and nesting material for birds and small mammals. That cover is also key to the survival of reptiles and amphibians. Cover implies not just protection from predators, but also from the elements. And deer use it to hide their newborn fawns while they go off to find something to eat. If you find a fawn hunkered down, don’t worry. The mother will come back!
Unlike the idealized lawn, our native grassland savannas include stands of woody, often thorny, vegetation, such as Agarita (Mahonia trifoliolata). These protected places provide “escape cover” from hawks, owls, and other predators. Quail have especially strict habitat requirements. Besides shrubs to hide in, they need tall grasses to hide their nests, as well as space between the grass clumps to roam in search of the seeds, forbs, berries, and insects they like to eat. Loss of this cover-rich grassland savanna habitat is one of the main reasons quail populations are declining.
Ducks like these Mallards actually consume the grass itself, not just the seeds. Photo: Mike Davis
Identifying grasses—not as hard as it seems!
Grass identification is more confusing than it needs to be largely because of the myriad of terms used to describe grass parts. Let’s start there. There are over 700 genera and 11,000 species of grass worldwide. In the Edwards Plateau ecoregion, there are 101 genera and 324 species. That’s a lot of variation! But the above ground structure of grass is mostly similar to forbs and woody plants. It’s just that, with grass, things like stems, leaves, and flowers are defined by different names. So here are some terms associated with a blade of grass that can help as you seek to better understand the grasses growing on your property.
Culms, nodes, internodes, stolons, and rhizomes
A grass culm serves basically the same function as the stem of a forb or the trunk of a tree. It supports the grass’ leaves, flowers, and fruits (its seeds), transports nutrients from the roots to other plant parts, and produces new cells called meristems. Grass stems consist of swollen nodes and internodes. The nodes are always solid. The internodes can be solid, semisolid, or hollow. The internodes in cross section are also typically round or elliptical. That’s one way to tell the difference between a grass and a sedge. The culms on sedges are often triangular, giving rise to the catchy rhyme that begins “Sedges have edges… .” Sedges don’t have nodes, thus the end of that same rhyme, “… and grasses have nodes all the way to the ground.”
In many grasses, the internodes remain very short for most of the annual life cycle. At this early stage, the grass plant appears like a clump of blades. One advantage of this low growth form is that it provides a measure of protection from grazing animals and wildfires. Then, as the grass approaches its flowering stage, the internodes become longer, pushing the reproductive part of the plant upward to attract pollinators.
In some grasses, the culms develop in a horizontal direction. If a horizontal culm develops above ground, as with Buffalograss (Buchloe dactyloides), it is called a stolon. If the culm develops underground, as with Johnsongrass (Sorghum halepense), it is called a rhizome. Some sod grasses, such as Bermuda Grass (Cynodon dactylon), have both stolons and rhizomes.
Leaves, sheaths, blades, ligules, and auricles
Another difference between grasses and sedges is how the leaves are arranged. On a sedge, the leaves are usually 3-ranked, meaning they come out on three sides of the stem. Grasses, on the other hand, are 2-ranked and alternate. That means the leaf at one node is oriented 180 degrees from the leaf at the previous one as they spiral up the stem. The grass leaf itself consists of the basal portion, called the sheath, which encloses the culm and the upper elongated portion of the leaf, often referred to as the blade. The sheath is usually spilt to its base on one side. But in some grasses the sheath is united from top to bottom.
Generally there is something called the ligule at the inside surface of the junction of the leaf sheath and the leaf blade. The ligule is usually either a thin, membranous rim or a ring of hairs. Occasionally there are finger-like appendages called auricles at the top of the sheath or the base of the blade, as with Indiangrass (Sorghastrum nutans). The ear-shaped auricles’ function is to keep the sheath open. These parts vary in appearance according to plant species, so they can be good clues, especially when trying to identify a grass that has not yet flowered. In particular, the ligule can be a very reliable characteristic in differentiating between two similar-looking grasses.
The leaf blades of most grasses are either flat and linear with parallel sides, or tapered to a point from or immediately above the base. Most grass blades have a prominent vein running down the center and a few less-prominent ribs. In some grasses, the vein can assist in identification. For example, the blades of Johnsongrass and Eastern Gamagrass (Tripsacum dactyloides) look very similar. But if you learn to look for the distinctive white vein found on Johnsongrass, you will have an easier time figuring out which one to pull and which one to leave alone. (Pull that invasive Johnsongrass!)
Inflorescence, spikelet, awn, lemma, palea, and floret
The inflorescence—the flowering portion of the grass plant—extends the stem from beyond the last leaf node. It is often one of the easiest ways to recognize many native grasses. There are three basic types of inflorescence: spike, raceme, and panicle, and a number of variations of these forms.
With the spike, the simplest grass inflorescence, the flowering bodies (called spikelets) are directly attached to the central axis (rachis) of the inflorescence. Canada Wildrye (Elymus canadensis) is a good example of this configuration. Also notice in the picture the stiff sharp bristles called awns. And what are the awns for? Basically, they are designed to assist with seed dispersal and burial and to give a measure of protection from animal predators.
Raceme grasses can look a lot like spike grasses. The difference is that the spikelets are individually attached to pedicels rather than being directly attached to the rachis. Sometimes, as with Sideoats Grama (Bouteloua curtipendula), you have to look closely to see the pedicels. The other interesting thing about sideoats grama is that all of the spikelets can be found on just one side of the inflorescence’s central axis—thus the name. Some grasses are a combination of both spike and raceme with flowering bodies attached to both pedicels and the rachis. This variation, called a spicate raceme, is what gives Little Bluestem (Schizachyrium scoparium) its distinctively busy look.
Click on any photo to zoom in for a full screen view.
Notice the awns on Canada Wildrye…
…and the pedicels on Sideoats Grama
The panicle, the third and most common inflorescence type, refers to any grass inflorescence where the spikelets are borne on branches rather than attached to the rachis or pedicels. The spikelets can be attached to the branches either directly or via pedicels. Panicle grasses come in a wide variety of forms. In some grasses, the fact that they are a panicle grass is fairly obvious, as with Switchgrass (Panicum virgatum). Others, like Bushy Bluestem (Andropogen glomeratus) have very contracted panicles, so it can be easily mistaken for a spike grass unless examined closely. And both of these are very different from the very distinct panicle found on Shortspiked Windmillgrass (Chloris subdolichostachya).
Short spike windmillgrass (left) vs. Bushy bluestem (center) vs. Switchgrass (right) are very different looking panicle grasses.
Let’s move in very close now. The small grass flowers are hidden by protective scales called bracts, which enclose the flowers. Typically, the grass spikelet has two series of bracts, which are actually modified leaves. The bottom two are referred to as glumes. In some grasses, the lower glume is greatly reduced or completely absent. The second pair of bracts contains the flower. These two bracts are referred to as the lemma and palea, and the entire structure is referred to as the floret. A spikelet can have one or multiple florets. The texture, shape, nervation, awn development, and surface features of the lemma make it a very reliable characteristic in grass identification. The presence and absence of awns, how many there are, and where they are attached (the lemma, palea, or glume) can also provide good clues. Care to guess how many awns there are on a grass with “Three-awn” in its name?
Grasses are seasonal!
Some native grasses can withstand our hot summers and others prefer cooler times. Most of those called cool season grasses start growing in the fall, grow slowly all winter, and mature in late spring. Those that wait for the weather to warm up, often waiting to mature until late summer or early fall, are called warm-season grasses. However, it’s not just a matter of when they choose to grow and mature. There is actually a biological reason for the difference. Remember photosynthesis? That’s how plants turn water and carbon dioxide into sugar and oxygen. Cool-season grasses use C3 photosynthesis which is the form common to most plants. Warm-season grasses use C4. You want to know, don’t you?
Well, C3 plants, as they are called, require lots of moisture and cooler temperatures. That’s why these kind of plants struggle during our hot, dry summers. An abundance of sunlight, high temperatures, and water stress cause one of the enzymes involved in the photosynthetic process to bind with oxygen. This greatly reduces the efficiency of the plant’s photosynthesis and water use. C4 plants, on the other hand, produce a four-carbon compound that prevents the binding of that particular enzyme to oxygen. Thus C4 plants can continue to thrive even in times of high summer heat and persistent drought.
Many of the grasses native to the Texas Hill Country are perennials. Some C3 grasses are annuals, blooming in the spring and spending the summer as seeds. Others are perennials, whose dying back to the ground in summer enables their roots to rest until the cooler weather returns. A few C3 grasses are native to the Hill Country. But many like Japanese brome (Bromus japonicus), Rescue Grass (Bromus catharticus), and Downy Brome (Cheatgrass, Bromus tectorum) have been introduced from cooler climates. The problem with these invasives is that they tend to grow mostly in winter. So when spring comes around, they inhibit spring growth of many of our heat-loving C4 natives.
Visit the Lady Bird Johnson Wildflower Center to see for yourself how burning and mowing influence grassland composition.
Some of our favorite cool- and warm-season grasses for your property
Grasslands come in many shapes and sizes. The largest temperate grassland in the world is the Eurasian steppe, which extends almost a fifth of the way around the world, from Hungary to China! But grasslands don’t have to be that big. One can be just a section of your backyard that you have turned into a “pocket prairie.” Or, if you own acreage, it can be a portion of your property where grasses naturally thrive. A healthy grassland has a mix of both cool-season and warm-season native grasses. The next article in this series on grasses will go into more depth on assessing, maintaining, and improving the grassland on your property. In the meantime, the first step is simply to find out what grasses are already growing on your property. Here are some of our favorites you might try to locate.
Cool-Season grasses for Central Texas:
Canada Wildrye—Bloom Period: May to June
Canada wildrye and its relative, Virginia Wildrye (Elymus Virginicus), are fairly easy to recognize by the spike form of their inflorescence and the presence of awns. The awns on Canada wildrye are longer and its seed heads tend to droop. The smaller seed heads on Virginia wildrye are generally straight. You might also look closely at the glumes; on Canada wildrye they form a sharp “V” shape at the bottom, as opposed to a “U” on Virginia wildrye. Then look closely at the ligule. It’s another good example of a grass that has auricles.
Broadleaf Woodoats— Bloom Period: June to September
Broadleaf Woodoats (Chasmanthium latifolium), commonly referred to as Inland Sea Oats, is easy to recognize by its showy, drooping panicle. This is one of just a few native grasses that will grow in light to dense shade. So it is often found growing in forest openings and along shaded streams. Woodoats provides shaded cover for newborn fawns and nesting cover for turkeys. And it is the host plant for several species of skipper butterflies. Cattle like it too and will quickly graze it out. So if your property has a history of overgrazing, it is a good grass to add back. And fortunately it is one of the easiest grasses from which to collect seeds. Just wait till the seed heads turn brown and the seeds fall easily into your hand. Then walk to another shady area and scatter the newly collected seeds.
Inland Sea oats can often be seen along streams.
Texas Wintergrass (Nassella leucotricha)—Bloom Time: April to May
Lots of people hate this grass, also known for good reason as speargrass. It’s easy to recognize by its one-seeded spikelets, each with a stiff or twisted awn that’s two to five inches long. These spear-like seeds readily stick to clothing or can become embedded in a pet’s skin. But these annoying awns do have a purpose. By coiling and uncoiling in response to moisture in the air, the seeds work their way through leaf litter and vegetation, firmly planting themselves into the ground. This grass may be a bit of an annoyance, but it is also an important food source for wildlife. In winter when food is scarce, deer will nibble its soft shoots. Turkey nibble its tender leaves, and quail eat its seeds.
Wildlife including deer, turkeys, and quail all benefit from often maligned Texas wintergrass.
Warm-Season Grasses for Central Texas:
Sideoats Grama—Bloom Time: June to November
We just had to include this one. That’s because it is the Texas state grass! Sideoats grama provides highly nutritious forage for livestock, so ranchers love it. It is also thought to have played a significant role in land recovery after the droughts of the 1930s. Wildlife love it too! Lots of birds, including turkeys, are said to use it for food, nesting material, and cover. And it is the host for two species of butterflies: the Green Skipper and the Dotted Skipper.
Little Bluestem—Bloom Time: August to December
Little Bluestem is one of our most abundant and recognizable grasses. It is considered one of the highly desirable “Big Four” tall grasses, together with Big Bluestem, Switchgrass, and Indiangrass. Historically, Little bluestem made up less than 30-40% of grassland composition. But, given population declines in the other three grasses, it is now often the dominant grass. It is quite striking in the fall when the plant turns a rich red-brown color that persists through much of the winter. Its fuzzy, white seeds are valuable as winter food for birds and small mammals. It also provides good nesting cover for ground-nesting birds and is the host plant for several species of skipper butterflies.
Southwestern Bristlegrass (Setaria scheelei)—Bloom Time: May to November
Also called Foxtail Grass for its single inflorescence that looks a bit like a bottle brush, this is another shade tolerant perennial grass. The seeds that fall away from the plant are eaten by quail, doves, and lots of songbirds. Turkey are said to strip the seeds right off the seed head. And it is said to be a favorite of Painted Buntings. Another grass that is also said to attract Painted Buntings is Texas Cupgrass (Eriochloa sericea).
Southwest bristlegrass
Little bluestem
Wildlife favorites - Southwest bristlegrass (left) and Little bluestem (right)
Switchgrass (Panicum virgatum) - Bloom Time: August to November
Switchgrass is one of our largest bunch grasses. Its seeds are eaten by ground feeding song and game birds. Ground nesting birds often use switchgrass as nesting sites, and it provides good cover for newborn fawns. Switchgrass is the larvae host for lots of skipper and satyr butterfly species. Switchgrass has an exceptionally long and dense root system, so it improves water infiltration. With a stability rating of 9 out of 10, Switchgrass also plays a important role in slowing flood waters and stabilizing stream banks.
Switchgrass has a stability rating of 9 (of 10), the equivalent of an anchored boulder.
Indiangrass—Bloom Time: September to November
Most of the year Indiangrass stays low and largely escapes notice. But come fall, its rich golden inflorescences suddenly peek up above the Little Bluestem and other grasses. This striking color is why it is often referred to as Yellow Indiangrass. Indiangrass produces lots of seeds that birds and small mammals like to eat. It is also good nesting cover, and is a larval food source for several butterfly species. It is also the state grass of our northern neighbor, Oklahoma, where it is even more prevalent.
Eastern Gamagrass—Bloom Time: April to September
Nicknamed “ice cream grass,” Eastern Gamagrass is another favorite of grazing cattle. It is said that when our early settlers came, Eastern gamagrass was almost wiped out by the livestock they brought with them. It is actually an early ancestor to corn, and its seed heads are unique. So it is easily recognizable when in bloom. But its leaves can be easily confused with Johnsongrass. Besides the characteristic white stripe on Johnsongrass, another differentiator is that Eastern Gamagrass tends to grow lower and wider than Johnsongrass. Deer are said to gobble up the seeds. And like Switchgrass, it is a good riparian stabilizer.
Inconspicuous most of the year, Indiangrass adds striking yellow color to fall landscapes.
Notice the unique seed heads on Eastern gamagrass.
According to Grasses of the Texas Hill Country: A Field Guide by Brian and Shirley Loflin, there are 280 of species of grass found in the Hill Country, of which approximately 215 species are native. But don’t feel overwhelmed. Start by learning to identify the nine grasses we just told you about. And then keep on going, one new species at a time. Grasses are notoriously hard to photograph in ways that facilitate identification, but don’t let that deter you from using iNaturalist or other plant ID apps to help you sort through the possibilities. It may be a good idea to invest in a good grass book. Here are a few suggestions:
Loflin, Brian and Shirley, Grasses of the Texas Hill County: A Field Guide. Lists 75 grasses found in the Texas Hill Country and includes great color photographs of their seed heads.
Gould, Frank, Common Texas Grasses: An Illustrated Guide. Lists 150 of the grasses most present across the state of Texas with line drawings of the plants and their various parts.
Shaw, Robert B., Texas A&M University Institute of Renewable Resources, Guide to Texas Grasses. Lists some 750 species with many illustrations.
Hatch, Stephan L., Umphres, Kelly S., and Ardoin, A. Jenét, Field Guide to Common Texas Grasses. Provides hundreds of common Texas grasses with good photos and drawings.
Members of the HELM team are continuously honing their skills by attending workshops on grasses and other topics of interest to Hays County landowners. We’re taking the summer off. But we’ll be back visiting with our Hays land stewards come fall. We are continuing to take requests for those fall visits.
And what will we do when we come out to your property? We will walk your property with you, identifying grasses and other plants as we go. We will make recommendations on improving soil and controlling erosion. We can provide helpful advice on attracting birds and other wildlife, preventing oak wilt, and much more.
So, if you own acreage in Hays County and would like to reserve a spot on our fall schedule (we only have 20 spots per season), go to https://www.beautifulhayscounty.org/helm/ and fill out our request form. And please help us spread the word!
Northern Harrier hunting low over grasslands. Photo: Mike Davis