Plant of the Week: The Big Four

To kick off our September celebration of the Chelsea Grasslands, this week we are featuring a classic collection of prairie grasses, commonly called "The Big Four." All four grasses are found along the High Line, although only three are used in the Chelsea Grasslands planting: Andropogon gerardii, Schizachyrium scoparium (a cultivar named 'Standing Ovation'), and Panicum virgatum (our cultivar of choice is 'Shenandoah). The final grass of the set, Sorghastrum nutans, can be found in the most northern section of the High Line, along 30th Street between 10th and 11th Avenues.

Photo by Cristina Macaya
The four grasses are representative of an ecosystem called the tallgrass prairie. Once covering 170 million acres in the north-central United States and Canada, only 4% of the original tallgrass prairie remains. The largest remnants of original tallgrass prairie are found in Kansas and Oklahoma. The same ecological factors that created a landscape of incredible native plant diversity also provided humans rich agricultural opportunities. Once settlers learned how to harness the land, the prairies were plowed for crops and grazed by livestock. This is the region we now recognize as "The Corn Belt."

These grasses are called "The Big Four" because of their dominance of the original tallgrass prairie. About 150 grass species were found in this ecosystem, but only 10 or so ever dominated any portion of the prairie.

Andropogon and Schizachyrium made up ¾ of the native tallgrass prairie, and Panicum and Sorghastrum are among a few others that rounded out the majority.

Lucky for those who enjoy gardens, these incredible grasses are also aesthetically effective when used in ornamental plantings. Here is a short description of each of "The Big Four" below and my recommendations.

Andropogon gerardii—The tallest of the four, you need plenty of space to plant this domineering grass. Some of the clumps in my garden have reached eight feet in height this year—and that's in approximately 18 inches of soil! Be sure to leave plenty of space around the individual clumps, as they will easily shade out anything else growing too close. The blooms arrive in late summer and are purplish-red with showy yellow anthers. The attractive foliage ranges from blue-green to red-bronze throughout the season. It is very tough and self-seeds easily—something to watch out for if you don't want it taking over.

Schizachyrium scoparium 'Standing Ovation'—We chose our cultivar because it was bred to stay upright longer. Little bluestem is an incredibly varied colored grass- blue, green, purple, sometimes even red. It's a manageable height and adds interest to any perennial planting. Little bluestem is found in all 50 states in a variety of conditions, making it a good option for many garden sites.

Photo by Ayinde Listhrop.

Panicum virgatum 'Shenandoah'—This cultivar of switchgrass has particularly strong colors - red, burgundy, bronze- which grow more vivid throughout the season. Panicum has the greatest impact in my garden when planted as a huge swath that drifts to the back of the bed. It is fairly easy to grow but struggled to survive during our tough winter in 2014-2015 (although this could very well be due to our particularly extreme conditions on the High Line).

Sorghastrum nutans—This is the only grass with which I do not have direct gardening experience, but our gardener up north says it's an extremely tough grass, great for difficult spots. The flowers are yellow (it is all called "yellow Indiangrass") and contrast nicely with the blue-green foliage. This grass is best planted in large masses, in a naturalistic garden or a wildflower planting.

Photo by Ayinde Listhrop.

The High Line's planting design is inspired by the self-seeded landscape that grew up between rail tracks after the trains stopped running in the 1980s. Today, the High Line includes more than 500 species of perennials, grasses, shrubs, and trees – each chosen for their hardiness, adaptability, diversity, and seasonal variation in color and texture. Some of the species that originally grew on the High Line's rail bed are reflected in the park landscape today. Every week we share one of our gardeners' current favorites with you.

Our horticultural team counts on members and friends like you to help keep the High Line beautiful and thriving. Join our community of supporters who play an essential role in the High Line's most important gardening projects.

Celebrating the Chelsea Grasslands is made possible, in part, by TD Bank—the Presenting Green Sponsor of the High Line.

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