Fall Plant Sale Preview: Native Grasses

Native grasses in the Piedmont Prairie. Photo by Sue Lannon.

 By Annabel Renwick
Horticulturist
Blomquist Garden of Native Plants at Duke Gardens

Autumn brings cooler, shorter days and helps the garden transition from summer into winter. By September many of our garden plants have finished blooming and frequently gone to seed, but not so in the Blomquist Garden’s Piedmont Prairie. Many of the late flowering, native grassland species are just coming into flower, such as the asters and goldenrods, so it’s not surprising that so many of these late flowering U.S. natives have been cultivated as garden plants worldwide, extending the enjoyment of gardens until the arrival of frost.

Eragrostis spectabilis.
Photo: USDA-NRCS Plants Database. 

September is also the time when many Southeastern native grasses are in flower along North Carolina roadsides. It may come as a surprise to many, but grasses do have flowers. The tiny flowers or spikelets are formed on a flowering stem, known as an inflorescence, with the more “ornate” grasses having highly branched inflorescences or panicles. Some of these panicles can be so intricately branched that they appear as airy mounds of transparent fine lace. Purple love grass (Eragrostis spectabilis) is one such species that has to be my favourite native grass planted in an ornamental setting. The gray goldenrod (Solidago nemoralis), Black-eyed Susan (Rudbeckia hirta) and smooth blue aster (Symphyotrichum laeve) make super planting companions with purple love grass.

Particularly striking are the taller grasses such as Indian grass (Sorghastrum nutans) with its masses of golden, oat-like  panicles, and sugarcane plume grass (Erianthus giganteus), with its clusters of silvery plumes shooting skyward. Stipa gigantea (giant feather grass), a stunning grass with arching flowering stems reaching 6 feet, is a stalwart of English Gardens but as a Mediterranean native doesn’t adapt well to North Carolina’s  hot and humid climate or heavy clay soil. Indian grass would easily make a marvelous replacement for S. gigantea in a North Carolina Garden.

Sorghastrum nutans in the Piedmont Prairie. Photo by Cathi Bodine.

The striking Erianthus giganteus works well at the back of a border and could replace the commonly grown (and sometimes invasive) Miscanthus sinensis (Chinese silver grass) in local gardens. Generally grasses prefer growing in sun or may tolerate partial sun, but they will not thrive in shade.  Many local grasses are drought tolerant and prefer nutrient poor soil; they will grow in our local heavy clay soil, and as with most grasses they are deer tolerant.

Grasses have been used in ornamental plantings in the U.S. for more than 100 years. One of the earliest proponents of incorporating native grasses into U.S. landscapes was the Danish-born Jens Jensen who, at the turn of the 20th century, belonged to the Prairie School style of design based on the Arts and Crafts movement established in Great Britain during the latter part of the 19th century. In more recent decades, Dutchman Piet Oudolf has echoed Jensen’s philosophy, designing and installing grass dominated landscapes including the Highline in New York City.

Oudolf has written many design books using grasses, but one of my favorites is “Gardening with Grasses,” by Michael King and Piet Oudolf (1998). A second recommendation is “The Encyclopedia of Grasses for Livable Landscapes,” by Rick Darke (2007).

Come to Saturday’s Fall Plant Sale and you’ll find these beautiful native grasses and many more.

FALL PLANT SALE DETAILS:
Date: Saturday, Sept. 29, 2018
Time: 9 a.m.-noon
Member benefits: Duke Gardens members get 10% off all purchases, plus access to the members-only previews sale from 8-9 a.m., and a full list of plants in advance! Join online or on site beginning at 7:30 a.m.
Parking: Free.
Pets not permitted. Please see Duke Gardens' pets policy here.
Wagons + boxes: Our supply is limited; please bring your own if possible, and you'll have more time to spend gathering beautiful plants.
Your support helps Duke Gardens to provide summer internships to aspiring horticulturists from across the nation.
Please see our event page for more information, and we'd love for you to spread the word by sharing the event on Facebook and inviting your friends.
Thank you!