Plant to Pick: ‘Blackhawks’ Big Bluestem

Ornamental grasses add height and texture to our gardens. ‘Blackhawks’ big bluestem also adds exceptional fall (and summer) colors to the perennial garden.

Many northern gardeners have cultivars of little bluestem (Schizachyrium scoparium) in their gardens. Much breeding work over the past decade or more on this plant has resulted in its smaller size and more refined appearance. The Minnesota-bred cultivar Little Heaven is one of several little bluestem options.

While little bluestem is a great choice, northern gardeners should really consider using big bluestem as well. This new cultivar, developed by plantsman Brent Horvath at Intrinsic Perennials in Chicago, is a much-improved version of the native big bluestem.

Blackhawks big bluestem in gardenThe foliage of ‘Blackhawks’ evolves throughout the growing season. The long, strappy leaves emerge green in spring but quickly start to take on some purple hues, even in June. Throughout the summer, those purple to red or almost bronze hues make their way throughout the foliage. By autumn, the purple foliage is so deep it looks almost black. It’s striking!

This is a big plant, eventually maturing at a height of 5 feet and more with the flowers and seed heads. It spreads 2 feet wide. It is perfect for the back of the perennial border, whether as an individual plant or in a group of plants to create screening or add drama.

Blackhawks is hardy in USDA Zones 3-9 so it works for all northern gardeners. It requires a full-sun site (a minimum of six hours of direct sunlight per day) and is not fussy when it comes to soils. Blackhawks can tolerate poor soils and dry sites. It will not tolerate consistently wet sites, however. No major insect pests or diseases affect Blackhawks.

The flowering stems rise above the foliage in late summer. The flowers are purplish, three-parted, fingerlike clusters up to 4 inches long. Some say they resemble turkey feet, which is another common name for big bluestem. The flowers can take the mature height of the plant up to close to 8 feet in moist soils but it generally stays shorter in dry soils.

Big bluestem is native to Minnesota and is an important component of the tallgrass prairies. It has sometimes been called the “monarch of the prairie.” It is also used as nesting material for birds and mammals. The straight species has not been used much in home gardens because of its large size and coarse habit, but the breeding improvements made in Blackhawks make it a perfect addition to your perennial gardens. It is a long-lived plant and can be used in naturalization areas and in restoring prairies. It is propagated via division.

This article by Debbie Lonnee originally appeared in the September/October 2020 issue of Northern Gardener. She works in the horticulture industry and gardens in South St. Paul.

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