Using Ornamental Grasses in Your Garden Design

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Garden designer Rebecca Sweet shared this advice for using ornamental grasses in the October 2013 issue of Horticulture:

using ornamental grasses

I can’t imagine designing a garden without tucking at least a few varieties of ornamental grasses among the traditional flowers, shrubs and trees. For one thing, they’re generally not very thirsty plants, nor are they fussy about soil conditions. And for another, they’re tolerant of most diseases and pests (deer and rabbits included). What’s not to love about a plant as hardy as that?!

Grasses also come in just about every size and color, making them ideal candidates to use throughout the garden, no matter its dimensions. For example, make a dramatic statement at the front of the border with shiny black mondo grass (Ophiopogon planiscapus ‘Nigrescens’; USDA Zones 6–9) that slowly grows to only six inches high. For the middle of the border, consider the steely blue color of blue oat grass (Helictotrichon sempervirens; Zones 4–8), growing to a manageable two- to three-foot dome. For the back of the border, consider the deep burgundy foliage of purple fountain grass (Pennisetum setaceum ‘Rubrum’; Zones 9–10), often towering over five feet tall.

In addition to the colors provided by the foliage itself, most grasses “flower” (taking the form of graceful inflorescence). These often last 8 to 10 weeks and add not only additional height to the grass, but often contrasting colors, too. For example, in the late spring delicate wands of pomegranate-pink inflorescences double the height of the normally 12-inch-tall and –wide ruby grass (Melinis nerviglumis ‘Pink Crystals’; Zones 8–10), which has blue-green foliage. The midsize feather reed grass (Calamagrostis xacutiflora ‘Karl Foerster’; Zones 4–9) puts on a late summer show when its tidy two-foot green foliage is transformed with towering four-foot-high stalks of golden, feather-like “flowers.”

Grasses are one of my favorite plants to use in the garden for late-season interest. Their fine and delicate foliage seems to catch fall’s slanted light better than any plant I can think of. They glow in the late afternoon as if lit from within. And should there be a soft breeze, they’ll gently sway, providing another much-needed design element—movement.
When winter hits, the grasses’ inflorescences turn tawny shades of tan and copper, I leave them on the plant for as long as possible. The seed-heads not only provide much-needed winter interest, but more importantly many grasses, such as prairie dropseed (Sporobolus heterolepis; Zones 3–9) and northern sea oats (Chasmanthium latifolium; Zones 3–8), provide nutritious seeds for hungry birds.

One of my favorite ways to elevate the status of an ornamental grass is to place it in an elegant container, nestled within the garden bed. Instead of filling the container with a complex mix of perennials, consider the “one-plant-per-pot” method, focusing the attention on a spectacular grass. This unexpected twist not only adds unique personality to your garden, but the grass’s finely textured foliage can often be better appreciated when viewed up close.

The next time you’re at the nursery, in addition to seeking out your favorite annuals and perennials, don’t forget the multiseason charm of ornamental grasses.

Image credit: Frederic Collin / Moment / Getty Images