Landscaping with Grasses
Authored by Leah Chester-Davis
The graceful, nodding plumes of ornamental grasses accentuated with morning or afternoon sunlight have a magical effect in any landscape. In addition to their sheer beauty, ornamental grasses can serve as screening, foundation, and focal or accent plants in perennial gardens, plants for slopes or tough spots, and even groundcovers if a low-growing type. Many are delightful in containers or window boxes.
What is ornamental grass?
Numerous plants are considered ornamental grasses, including true grasses and plants that have a grass-like appearance such as sedges, rushes, and cattails. Ornamental grasses are available in many sizes, shapes, textures, and colors. They add architectural elements, movement, and year-round interest. They belong in just about every landscape.
Choosing ornamental grasses for your landscape
When considering ornamental grasses for the landscape, here are a few guidelines to keep in mind.
Cool season and warm season
Grasses are typically divided into either cool season or warm season based on the time of year they most actively grow.
Cool-season grasses
Cool-season grasses will look their best when the temperatures are between around 32 and 75 degrees F. They are most vibrant in spring and early summer when they put out flowers and seedheads. They may go dormant in summer heat but rejuvenate when the cooler, fall temperatures arrive. Cool-season grasses include blue fescue (Festuca glauca), Zones 4 to 8, and ‘Karl Foerster’ feather reed grass (Calamagrostis x acutiflora), Zones 5 to 9.
Warm-season grasses
Warm-season grasses are dormant through the winter. They green up in the spring and thrive through the hot summer. In the late summer or early fall, they will flower and go to seed. A few warm-season grasses include purple fountain grass (Pennisetum setaceum ‘Rubrum’), Zones 9 and 10; Northern sea oats (Chasmanthium latifolium), Zones 3 to 8; switch grass (Panicum virgatum), Zones 5 to 9; and Japanese silver grass (Miscanthus sp.), Zones 4 to 9.
Shade or part-shade
A few of the ornamental grasses are quite at home in shady areas, and they lend both texture and interest when paired with other shade plants such as hostas and heucheras. Japanese Hakone Grass, sometimes called Japanese forest grass, grows in dense, graceful mounds that add lovely contrast with its green, gold, or variegated foliage, depending on the cultivar. It grows in Zones 5 to 9 and can also handle part sun. A grass that can handle part shade and full sun is purple moor grass (Molinia caerulea), Zones 5 to 8. Give it plenty of room to grow as the mound of foliage grows to 3 feet tall and the flowering stalks even taller, to 5 feet.
Interest and impact of ornamental grasses
Ornamental grasses have great impact in the landscape when planted en masse. A large sweep of pink muhlygrass (Muhlenbergia capillaris), Zones 5 to 9, is a native grass that is a showstopper when it blooms in the fall. Clouds of soft pink flower stalks shimmer in the afternoon sun. If you have space, you can’t go wrong planting masses of this grass. It is stunning at entrances to a property, in a large swath around mailboxes, or massed in mixed borders. Muhlygrass is also available in a white variety. This grass is lovely with prairie flowers such as purple coneflowers (Echinacea).
Other incredible selections include ‘Hameln’ fountain grass (Pennisetum alopecuroides), Zones 4 to 9, which has a mounding habit and is a great choice to pair with late-season perennials or with shrubs in the mixed border. Fine-textured green grass blades grow to about 3 feet tall. In late summer to early fall, it blooms with soft, wheat-shaped seed heads, which add interest through the winter. Its foliage turns gold in the fall.
Using grasses as edging along walkways or borders
Ornamental grasses can serve as accents to borders or edging plants along walkways. When selecting plants for this purpose look for ornamental grasses that are low growing, no more than a foot or so tall so they won’t hide plants that are planted behind them. A couple of options are blue fescue (Festuca glauca), Zones 4 to 8, which delivers an architectural element with its short, blue-green spikes and a contrast to greens, golds, and burgundies in the landscape. Sedges are other options. Many grow to about 18 inches but check the tag information as they vary greatly depending on the type.
Grasses as groundcover
If you have an area of your lawn that may be difficult to mow or maintain, or if you simply prefer a lawn that looks like turf but requires minimal work, consider sedges. They may be just the ticket in a shady spot where you have limited luck with turfgrass. Pennsylvania sedge (Carex pensylvanica) is fine textured and can help cover difficult sites, particularly in shady areas. Some of the more common options include dwarf mondo grass and creeping lilyturf (Liriope spicata).
Using grasses in pots
Some of the most striking and attention-getting ways to enjoy ornamental grasses is to include them in containers, but they are equally at home in other areas. Carex EverColor ‘Everillo’, Zones 5 to 9, is an electric green that is stunning cascading over a container all its own. Or pair it with other plants. New Zealand sedge, Carex testacea, Zones 6 to 10, turns a brilliant orange in the fall, lending an autumnal flair to any container and great for pairing with any fall-themed plant material.
Purple fountain grass is a stunner wherever it grows. Place it in a large container mixed with annuals, perennials, or both. Consider petunias, pentas, salvia, coneflowers, or sedums. Pennisetum ‘Fireworks’ is a variegated cultivar with white and cream near its base and a burgundy midvein that gives it the appearance of stripes. It is an annual in most areas as it is hardy only in Zones 9 and 10.
Go bold with ornamental millet. Pennisetum glaucum. ‘Purple Majesty’, Zones 2 to 11, and other selections are for those who have plenty of room and wish to add a striking focal point or backdrop to a perennial garden. It is amazing in containers, but you will need a large one as this plant grows 2 to 5 feet tall. When it is paired with brightly colored plants such as yellow or orange celosia, black-eyed Susan, lantana, or purple coneflower, it’s hard to take your eyes off this plant. A couple of compact options that grow to 3 feet tall and are great for containers are ‘Purple Barron’ and ‘Purple Jester’.
One of the best ways to begin landscaping with marvelous grasses is to simply give them a try. Others’ landscapes, botanical gardens, magazines, Pinterest, and Instagram are great places for ideas. The options are endless and the rewards of gardening with these plants are plentiful.
