Ornamental Grasses: 101

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Carex is happy in the shade.

A workhorse in just about any landscape, ornamental grasses are as varied as the gardens they inhabit. They come in many sizes and shapes, from small clumps of carex at home in the shade to the towering, showy panicum that thrive in our summer heat and humidity.

Ornamental grasses came into gardening vogue about 30 years ago with the help of internationally acclaimed landscape designer Wolfgang Oehme. His signature “naturalized landscapes” often included mass plantings of grasses along with native flowers like Black Eye Susans, coneflowers, and Joe Pye Weed. One of Oehme’s most prominent landscape projects was the renovated Ronald Reagan National Airport, where ornamental grasses and their companion plantings thrive today.

New York City’s acclaimed “High Line” garden is another example of ornamental grasses thriving in a difficult, urban environment.

Grasses are incredibly versatile – beautiful mixed in a perennial border, excellent when used in pots, and can make great specimen plants. The larger varieties are good for screening busy roads or, ahem, neighbors. Most are drought resistant and very low maintenance. And as an added bonus, grasses are not a favorite food of our resident deer population. Many of you are probably familiar with the more commonly used grasses like fountain grass, maiden grass and pampas grass. Here are a couple of lesser known varieties that are worth checking out:

Panicum virgatum, commonly known as switch grass is a hardy native perennial grass that grows from to three to six feet tall with stiff upright clumps and showy, airy flowers of pink, red or silver in mid- to late-summer. Switchgrass attracts birds, and is useful for screening, water gardens or prairie gardens. The variety ‘Northwind’ has wide, bluish foliage and an upright habit that is focal point in a garden or landscape. ‘Cloud Nine’ grows 6 to 8 feet tall, while bushier ‘Prairie Sky’ gets half as big. ‘Heavy Metal’ has beautiful frosted lavender blue foliage that can grow to 5 feet tall. Switch grasses have lovely fall-through-winter inflorescenses – the plumes or seed heads – which range from spear-like to feathery.

Muhlenbergia capillaris is a colorful favorite.

Sporobolis heterolepis or prairie dropseed, is a North American native. This smallish grass – its average growth is three feet by three feet – is a good choice for ground cover and foundation plantings. Its graceful foliage is lovely in the fall, turning gold to light bronze. Tiny rounded

mature seeds drop to the ground from their hulls in autumn giving this grass its common name.

Schizachyrium scoparium or ‘Little Bluestem,’ another native grass, typically grows two to four feet tall. It’s an upright grass with a tinge of blue at the base. Purplish-bronze flowers rise above the foliage in August. An outstanding feature of this grass is the bronze-orange fall foliage color.

Muhlenbergia capillaris or Pink muhly grass is one of our favorites. Its cotton candy pink plumes are show-stoppers, especially when planted in masses of three or more plants. This little grass (24″ – 36” high and wide) is perfect for smaller gardens. Pink muhly prefers to be on the dry side during the winter months, so make sure to plant it in a well-drained site.

Popular in many gardens, switch grass grows between 3 and 6 feet.

Carex or sedge grass grows shorter and bushier than most ornamental grasses and unlike their cousins, they are happy growing in the shade. They are great in the middle or front of the border and in containers, and are lovely planted with hosta and coral bells. ‘Evergold’ is a variety that tolerates moist soils, and like most ornamental grasses, is deer resistant.

Another shade loving grass is Japanese Forest Grass, or Hakonechloa. It is low and mounding, rarely growing taller than a foot. Like carex, it is a welcome addition to the shade garden, its foliage providing a contrasting bright spot in a shady nook.

Most ornamental grasses prefer full sun, though some, like sedge and Japanese Forest grass tolerate or prefer shade. Grasses generally need to be cut back hard in early spring. If after cutting it back you see that the center of the clump is brown and dying, it’s time to dig up and divide. Easy to care for, established ornamental grasses rarely need fertilization and don’t require irrigation except in very sandy or drought conditions.