Sorghastrum nutans, Indian Grass – 4 (4)

By Catherine Macleod

The most breathtaking quality of Sorghastrum nutans — one of the most beautiful of native grasses in my opinion — is animation. In even the subtlest of breezes Indian grass, as it’s commonly known, creates a ballet of movement and sound. From dawn to dusk light transforms its majestic foliage and delicate seed heads, recalling the vast tallgrass prairies where it grew and supported the way of life of the Plains First Nations.

The plant’s botanical name captures its qualities: the species name nutans comes from the Latin for swaying, while the genus name Sorghastrum is of Greek origin and means “a poor imitation of sorghum”. (Sorghum is a tropical cereal grass to which early European taxonomists no doubt compared Indian grass.)

Sorghastrum nutans, a member of the Poaceae or Gramineae family, grows naturally from one to 2.5 metres high (approximately three to eight feet) almost anywhere – in woodlands, sandy or clay soils. In clay it takes longer to mature; in sandy soils with less moisture, it tends to be shorter. Its efficient fibrous root systems (which make up about two-thirds of the plant’s total biomass) make Indian grass especially drought-resistant. Reaching depths of two metres (seven feet), it was these root systems that helped build the rich soils of the tallgrass prairie over thousands of years.

Indian grass grows in lateral shoots from its base, keeping this upright plant compact. Seeds are borne on golden plume-like seed heads called panicles. What we call the flower is actually a complex group of structures, arranged in clusters on a stem. In grass terminology this arrangement is called an inflorescence. The multi-branched and very open flower of S. nutans is made up of delicate stemmed spikelets, consisting of a central axis – or rachlis – and florets..

The stems or culms of Sorghastrum nutans are herbaceous, hollow and cylindrical. Each leaf is composed of three parts — a vertical sheath, which grows from a node and wraps around the stem, a ligule (a protective membrane of thin hairs at the juncture of the sheath), and a blade, the part of the leaf above the sheath. The ligule, which on Indian grass looks like a couple of erect pointed lobes, helps identify the plant even when it is not in flower.

The blades of S. nutans are usually open and narrow with parallel veins and a large median vein called a midrib. The leaves range from six to12 millimetres (1/4 to 1/2 inch) wide and 20-30 centimetres (eight to 12 inches) long.
Foliage colour is generally light to medium green, but can vary from gray-green to almost blue. Also known as gold beard grass, Indian grass flowers mature from the bright yellows of summer to dramatic bronzes in autumn.

The unusual way grass grows contributes to its survival. Most plants grow from the tips of their leaves and branches. Grasses, however, have two distinct growing points — at the base of each leaf and just above each growth node on the stem. This growth pattern means that grass can keep on growing even after cutting, cropping by animals or fire.

A clumping warm-season grass, Indian grass is a slow steady grower, ideal in mass plantings and great for prairie restoration and erosion control. S. nutans is also being hailed as one of the top native grasses for the ornamental garden, in mass plantings or as a single dramatic specimen.

Native to Manitoba, Ontario, Quebec, south through New England to Florida, west to Texas and back north to North Dakota, this splendid grass faces an uncertain future. Agriculture and other human activities have reduced its natural range from over a million square kilometres (400,000 square miles) to one percent of the magnificent original. Pockets of tallgrass prairie, where Sorghastrum nutans thrives, still exist in the Flint Hills of Kansas, the Tallgrass Prairie Preserve in Oklahoma, the Living Prairie Museum in Winnipeg, Manitoba, the Walpole Island First Nation near Wallaceburg, Ontario, Norfolk Sand Plain in Brantford, Ontario and a few other locales.

North America’s native peoples wove Indian grass into baskets and mats and dyed and threaded it with beads, bark and quills for ornament. They shared the “sea of grass” – the tallgrass prairie that is a mix of grasses, sedges and wildflowers such as black-eyed Susan (Rudbeckia hirta), wild bergamot (Monarda fistulosa) and butterfly milkweed (Asclepias tuberosa) – with grazing bison and elk herds, plains wolves, grizzly bears, butterflies, bumblebees, ducks, geese and red-winged blackbirds. Today, what remains of the tallgrass prairie is home to ground-nesting birds and butterflies.

By planting Sorghastrum nutans and its ecological counterparts in our gardens we create tiny bits of prairie where birds and insects can once again find food and refuge.

Catherine Macleod is a writer based in Kincardine, Ontario. With her horticulturist and photographer husband, Martin Quinn, Catherine co-authored Grass Scapes: Gardening with Hardy Ornamental Grasses, published this year by Whitecap Books, Vancouver, British Columbia. Email cmacleod@hurontel.on.ca or visit www.martinquinn.com.