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Little Bluestem Blends for the East
by James C. Grimes
When I was growing up on the eastern tip of Long Island, New York, little bluestem was everywhere. It is a major component of our maritime grasslands, where it mixes beautifully with the colors and textures of common sedge, crinkled hairgrass, and Maryland stiff aster. Little bluestem is a warm-season grass that is native throughout most of the United States and Canada. I had always taken this versatile native grass for granted and so never considered its potential as a lawn.
Then, several years ago, a young botanist named Eric Lamont and I were asked to replant the roughs and nonplay areas of a local golf course. We needed a mix of short native grasses that required no pesticides or irrigation and only occasional mowing. Lamont suggested little bluestem (Schizachyrium scoparium), common or Pennsylvania sedge (Carex pensylvanica), and tufted hairgrass (Deschampsia flexuosa), which he explained would create a maritime community. It sounded great. I began to see maritime grasses everywhere. I noticed lawns on older properties in the area—lawns that no one had planted but had emerged after years of only occasional mowing. They were the same maritime grasses and forbs Lamont had recommended. Vastly different from the Merion bluegrass sod typically used for turf in our area, these native lawns had more character and did not need irrigation or fertilization. They were fine on their own.
A lawn of little bluestem and hard fescue that has been cut regularly and irrigated forms a beautiful green carpet of grass in August. (Photo: James C. Grimes)
My investigation of these grasses has involved years of trial-and-error experimentation with many other native grasses and forbs. I've tried different ways of creating grasslands, propagating plants, and maintaining stands. Here are my best recommendations for success.
Preparing the SeedBed
Grasses can be established from seed, plugs, divisions, or sod. As seed is the most commonly available and least expensive alternative, it is often best for large lawns or situations where budget makes other methods impractical. However, little bluestem, like many warm-season grasses, is fairly slow to establish from seed, taking two or three seasons to mature. Plugs, divisions, and sod will establish more rapidly and also give you the opportunity to place masses of tall or short grasses where you want them.
Analyze the suitability of the site
For little bluestem, direct sun is not just an option, it's a requirement. Warm-season grasses will not tolerate any shade. However, most warm-season grasses are fairly tolerant of poor soil. In sandy or dry soil, little bluestem tends to clump; in deeper, heavier soil, it spreads. If the lawn is going to be mowed regularly, the plant's habit of clumping or spreading is less significant. But if the grasses are not mowed regularly or if the desired effect is to let the plants grow and flower, rich soils may be a problem.
Bluestem isn't for every situation. Warm-season grasses tend to bend or fall over when grown with too much moisture. An alternative for more moist soils is broomsedge (Andropogon virginicus), which looks very much like little bluestem, except it is slightly taller and has leaves along the flower stem. In shady areas, where little bluestem would languish, I use tufted hairgrass and common sedge or some types of fine fescue.
Prepare the soil and control weeds
Soils can be adjusted to some degree to accommodate the desired grasses. When working in old farm fields, I routinely strip off a portion of the thick, heavy farm soil and supplement it with sand and organic matter. During this process, I vary the thickness and texture of soil throughout the site. Doing so creates conditions for a diverse plant community and a more natural effect.
Controlling weeds is the most important step in establishing a natural-looking grassland, especially when starting a native lawn in farm soil where undesirable growth has not been controlled. Omitting this step is a common but costly mistake. Weeds must be controlled for warm-season grasses to thrive, as they are not terribly aggressive in the seedling stage and are easily overrun by more aggressive broadleaf weeds and nonnative grasses.
Weeds can be controlled with mechanical or chemical means. Each approach has strengths and weaknesses.
I prefer to till if the soil needs to be amended or changed. On a small area, I remove the first 2 to 3 inches of soil, getting rid of most of the roots and seeds of undesirable plants. In farm soils, which in my area tend to be fairly fine-textured and poorly drained, I adjust the pH and amend with coarse sand and organic matter (approximately 1 to 2 inches of each). The areas are allowed to sit for several weeks to allow remaining weed seeds to germinate, and then the soil is tilled again. This process is repeated at least one more time to be sure all weeds are gone. The last tilling prior to seeding is very light—only 1 to 2 inches deep—to avoid bringing any remaining weed seeds to the surface.
One caution about repeated tilling: If the soil is fine-textured, tilling may destroy its structure, leaving you with soil that has the consistency of flour. Since you cannot repair the soil once it is pulverized, you may want to consider using a contact herbicide, such as Roundup, after the first tilling. Then, prior, to seeding, just scratch the surface with a rake.
If you are fortunate enough to have natural soil that has not been disturbed or areas that are already seeded as lawn, you may consider not tilling at all. In this situation, I use a contact herbicide spray to control unwanted growth. Woody shrubs are removed by hand.
If you prefer not to use chemicals and the area is small enough, you can cover it with black plastic to kill the existing growth. After the growth is dead, till the area lightly or rake prior to planting.
The length of time it takes to get rid of undesirable growth depends on a variety of factors. Optimally, having one full growing season to accomplish this task is worth the wait and is less costly in the long run.
Seeding
Seeding of warm-season grasses differs from that of conventional cool-season lawn grasses. Cool-season grass seed tends to be small and clean, flowing easily through seeding equipment, such as broadcast seeders or standard lawn overseeders. But the physical character of warm-season grass seed is different. A little bluestem, big bluestem, or Indian grass seed has a long, feathery appendage called an awn that gives the seed the texture of a goose feather. These seeds do not run smoothly through a gravity-fed spreader, and trying to hand broadcast the seed is like attempting to spread cottonballs. The seed literally bunches together, making it difficult to spread evenly or make good contact with the soil. However, there are several good alternative seeding methods for warm-season grasses.
Hydroseeding and drill seeding
Both hydroseeding and drill seeding work well for warm-season grasses. With hydroseeding, the seed is mixed in a large tank with water and a binder, such as paper pulp or newspaper fiber, and sprayed on the ground. This method is most commonly used along roadsides, mall areas, and on steep slopes.
Drill seeding works well on large, flat, or rolling areas. A seed drill is a piece of equipment attached to a tractor. As it is towed along, it cuts a furrow, plants the seed approximately 1/4 to 1/2 inch deep, and closes the furrow. We use ours on expansive areas and existing grasslands where we want to add warm-season grasses or forbs.
There is one drawback to using a drill seeder: It places the seed on 6- to 8-inch centers, resulting in a "hair transplant" look. In spite of this, drill seeding is better than hydroseeding or hand seeding, as less seed is lost to the wind and birds.
Hand broadcasting
For small areas and touch-up seeding, we still hand broadcast. I usually mix the seed thoroughly with vermiculite or sand, especially when using a fine seed such as hairgrass or petticoat grass (Eragrostis spectabilis). This helps to spread the seed more evenly. After seeding, rough up the area to cover some of the seed. Then water well to provide good soil contact.
Seeding rates
Depending on the purity of the seed and whether you would like a pure stand or a mixture, the seeding rate will vary.
Warm-season and many native grasses tend to have quite a bit of chaff (anything that's not seed) mixed with the seed. This can have a dramatic effect on the actual amount of seed you are buying. Most recommended seeding rates are listed as PLS, for "pure live seed." For example, if you are trying to seed little bluestem, which is commonly about 40 to 50 percent PLS, at a rate of 25 pounds per acre, you will need between 50 and 60 pounds of bulk seed to plant 1 acre.
When ordering seed, specify your needs in PLS and most seed suppliers will provide it accordingly. If the supplier doesn't know what PLS is, usually you will get straight bulk seed. Just be sure the price reflects it. I've had a few occasions when the price was quoted as PLS but we received only the bulk amount.
When to Plant
Sowing grasses at the proper time is based on an understanding of their life cycles. Warm-season and cool-season grasses have different growth patterns.
Warm-season grasses break dormancy in late May. The plants' deep, well-developed root systems provide ample water through the hot growing season. As summer comes to an end, the plants go to seed. By the time the seeds are ripe, the cooler fall temperatures and shorter days prevent them from germinating. The seed overwinters in the soil and germinates when the soil warms up sufficiently the following summer.
Warm-season grasses need warm temperatures for both germination and growth. Spring seedings tend to favor the warm-season grasses and fall-flowering forbs (nongrass herbaceous plants).
Conventional lawn grasses, mostly cool-season types, emerge in spring and put on their growth during the cool, moist weather, usually flowering and setting seed by early summer. Most of these grasses go dormant during the hottest part of the summer. When late summer rains come, if any seed has developed and fallen to the ground, it will germinate in the warm weather of early fall and continue to grow in the cooler temperatures of late fall. Cool-season grasses germinate in warm temperatures and grow during cool temperatures.
Late summer and fall seedings favor the cool-season grasses and spring-flowering forbs. Temperatures are warm enough for both types of grasses to germinate, but the nights are cooler, a condition that makes the cool-season grasses thrive. Cool-season grasses, if not well established by the time hot weather arrives, will succumb to the heat.
I prefer to plant mixes that contain both warm-season and cool-season grasses with forbs in mid-August. The days are getting short enough and the nights are cool enough to prevent many of the annual weeds from germinating. But the temperatures are still warm enough for little bluestem and other warm-season grasses to germinate and develop before winter. Cool-season grasses germinate and grow well in these conditions. You can determine the success of the warm-season grasses by October, since, even though they are seedlings, they will still display their typical red fall color. If the germination rate seems light, scratch or drill in additional seed the following spring when the soil warms up.
Remember: Spring seeding favors warm-season grasses and fall-flowering forbs; late-summer seeding favors cool-season grasses and spring-flowering forbs.
Planting divisions, sod, and plugs
Divisions are produced by lifting established plants and dividing them into small sections. Care must be taken to maintain active growing points in each division. Divisions are commonly used to reproduce hybrids or a clonal selection that would not come true from seed. You can buy divisions of little bluestem and other grasses, but they tend to look stiff and unnatural. They only work well in spring when the plants are still dormant. Late-summer and fall divisions are prone to winterkill and not worth the effort.
Sod is an entire section of existing prairie that has been removed—everything that is growing, with as much root system as can be carried. You must have permission to do this kind of harvesting.
Plugging is the method I use most often. Plugs are small potted plants, usually propagated from seed. I take seed I have collected locally and pot up plugs to supplement seeded areas. The plugs can be planted before or after seeding and help us maintain some of the local gene pool in all our plantings. Little bluestem started in a greenhouse in winter will be large enough to bloom in August. Plugs are also available from several suppliers in a variety of sizes, from 1-inch cell packs, to peat pots, and larger containers.
For small areas, plugs can be more effective than seeding. Plugs can be planted any time during the growing season. Even though they are small, the 2-inch plants don't seem to be at a disadvantage and grow well even in the middle of summer, provided they have enough water when planted. Plugs also allow exact placement of plants. I use the chuck-and-duck method—throw the plugs out in a random fashion and plant them where they land.
Wildflowers to Add as Accents
Maryland aster (Chrysopsis mariana) (Photo: James C. Grimes)
A native lawn of little bluestem is informal, durable, and beautiful, especially when accented with wildflowers. In spring, bits of color appear with the blooms of plants such as pussytoes (Antennaria plantaginifolia), blue-eyed grass (Sisyrinchium angustifolium), and bird's foot violet (Viola pedata). In July and August, when other lawns seem to shut down, little bluestem shows off its purple-blue seed stalks, then turns the color of red wine. This, combined with blooms such as those of white hyssop-leaved thoroughwort (Eupatorium hyssopifolium), Maryland aster (Chrysopsis mariana), yellow Maryland aster (C. falcata), purple gayfeather (Liatris spicata), blue stiff aster (Aster linariifolius), and heath aster (A. ericoides) creates an intriguing blend of fall color. If taller spring wildflowers are used, mow the lawn early, before the flowers appear. Do not mow again until after the wildflowers bloom, and then use the mower to deadhead the flowers. -- J.C.G.
Managing a Native Lawn
The amount of maintenance a native grassland requires depends on the level of refinement to which you are accustomed or that you desire.
During establishment, expect some bare spots and weeds. Not all areas of a planting will establish at the same rate The same inconsistencies in soil and light that affect a traditional lawn will also affect a native grassland. I prefer to look at these trouble spots as opportunities for more diversity. These areas can be touched up with low-growing forbs that add seasonal color and texture to the grasses. A lovely companion for little bluestem is pussytoes (Antennaria plantaginifolia), which has woolly, whitish green leaves, grows only 1 to 2 inches tall, and is drought tolerant.
Although a native grassland only needs minimal care once it is established, it is not completely self-sustaining. If left unattended, over time it will evolve to more woody vegetation. To maintain the area as a grassland, some intervention will be necessary. Historically, grasslands in my area were burned every few years in the spring. The fire controlled woody weeds, such as bittersweet and honeysuckle, and helped control ticks. However, New York and other states have outlawed burning without a special permit, so mowing is a more common management tool.
Mowing requirements depend on your taste. Warm-season grasses like little bluestem can be mowed as low as 3 inches, but 5 inches is better. To create a more natural look and further minimize maintenance, I mow every week or so beginning in late April through the Fourth of July. This is the time when cool-season grasses put on most of their growth; if left too long between mowings, they may look shabby.
In June, hairgrass, by far the most graceful of any grass, sends up its wiry seed stalk. By early July, I stop mowing to allow the warm-season grasses and late-flowering forbs to develop. In high-traffic, high-visibility areas, I mow only as needed for a look that's informal but not seedy. The little bluestem and forbs, such as gayfeather (Liatris spicata) and asters (Aster species), will begin to flower and set seed, providing food for wildlife and self-sowing to fill in the grassland. Everything is left tall for the winter. The following April, I mow again and repeat the process.
Insects are an occasional problem in these grasslands but are usually not serious enough to warrant any action. Warm-season grasses have well-developed root systems, which help them endure insect attacks. Hard fescue and sheep fescue are more susceptible to injury. In areas where grubs are a consistent problem for cool-season grasses, we overseed with warm-season grasses. During wet summers on irrigated sites, rust can sometimes be a problem. This is almost always related to how the site is being managed; cutting back on the amount of overhead water usually solves the problem.
Judicious neglect seems to be the best approach to native grasslands. All that's needed is occasional mowing. Since fertilizer seems to be the catalyst for most problems we've encountered, we only use a starter fertilizer during initial establishment and then feed only every other year or so if the grassland appears to be weak. If fertilization is necessary, we feed at only half the recommended rate.
James C. Grimes is the owner of Fort Pond Native Plants in Montauk, Long Island, New York.