By Janine Anderson, CPH
Professional Member, APLD
Ornamental grasses are finely textured plants that lend a casual and relaxed feeling to your landscape. They move with breezes and capture sunlight, changing with the seasons and time of day. They also provide food, nest material, and cover for birds.
Pheasant’s Tail Grass (Anemanthele lessoniana) stands out in this mixed border. More about this New Zealand native is under “Caveats and Conclusions.” Design and photo courtesy of Octavia Chambliss
Primary considerations when selecting ornamental grasses are site conditions—sun or shade, wet or dry, soil type (e.g., sand or clay), space, and companion plants. Although they are inherently informal, ornamental grasses are also effective in more traditional landscapes, for example, when planted along a formal entryway.
There are many exquisitely beautiful grasses and grass-like plants, but landscape designers favor those they have found to perform well in the landscape in addition to being stunning. This article provides a sample of some of the best selections.
Maiden Grasses (Miscanthus sinensis)
Although the variety of maiden grasses available at local garden centers
can be overwhelming, area landscape designers are almost unanimously
enthusiastic about a mere handful of the selections. These deciduous
grasses offer three-season interest, with foliage emerging in spring,
followed by flowers, seed heads, and fall colors that shimmer in the autumn
light.
Maiden grasses are not drought tolerant and will look their best with some summer irrigation, a bright location, and minimal or no fertilization. Cut them to the ground in winter before the new foliage emerges.
The white-variegated foliage of Miscanthus sinensis ‘Morning Light’ looks silvery blue in a border and has a fine, airy texture. It lightens dark corners and is effective by itself or en masse. The fine-foliaged ‘Adagio’ forms a petite mound spiked with feathery seed head plumes in August. The pinkish flowers of ‘Yaku Jima’ emerge in September, turning beige later in the fall as the seeds mature, while the foliage takes on orange tones. ‘Gold Bar’ is a narrow, vertical selection with clean, bold variegated foliage that maintains its upright form.
Landscape designer Susan Picquelle has paired silvery ‘Morning Light’ maiden grass with other whites. The hemlock to the left is Tsuga canadensis ‘Gentsch White’; beside it is the mock orange Philadelphus virginalis ‘Innocence’. Photo courtesy of Susan Picquelle
Fountain Grasses (Pennisetum)
Fountain grasses are aptly named. From late June to October, a fountain of
flowers rise and cascade above the basal clump of foliage.
Fountain grasses require full sun and can handle a hot spot. The soil should be well drained (avoid wet areas), and only occasional watering is needed during summer dry spells. As with maiden grass, fountain grass should be cut to the ground in fall or winter after the seed heads are no longer attractive.
Area designers are partial to varieties of the species Pennisetum alopecuroides. Designer Laura Kleppe considers two diminutive selections, ‘Little Bunny’ and ‘Hameln’, her standbys. Also favored is ‘Burgundy Bunny’, which stays under two feet tall and has red-tinged foliage that emerges in spring.
Pennisetum orientale ’Karley Rose’ is a popular selection whose rose-colored flower spikes rise above the foliage in late summer. Although Karley Rose is a Great Plant Pick for our region, some designers have found that it self-sows, necessitating hours of weeding to eradicate the seedlings that pop up everywhere.
Designer Octavia Chambliss likes to edge planting beds with Pennisetum alopecuroides ‘Burgundy Bunny’. Photo courtesy of Octavia Chambliss
Japanese Forest Grasses (Hakonechloa macra)
Few grasses inspire more awe than Hakonechloa, native to the
mountainous Hakone region of Japan. Designer Susan Picquelle considers
Hakone grass the most glorious grass, especially when viewed from above.
Although Hakone grass stays well under two feet tall, some varieties spread
to five feet or more. It is dramatic when lining a walkway, but also eye
popping in combination with other plants.
Hakone grass does well in shade and can handle some sun, but hot afternoon sun should be avoided. Regular water during dry periods will keep it looking lush and full. As with other deciduous grasses, Japanese Forest Grass can be cut to the ground in winter before the new foliage emerges.
Many designers favor the variety ‘Aureola’. With leaves striped green and gold, it appears as a true yellow in the landscape, and designer Susan Picquelle believes it coordinates well with other plants. Others also use the chartreuse variety ‘All Gold’, as well as the more diminutive selection, ‘Beni Kaze’. At three feet wide, the green ‘Beni Kaze’ takes on tones of deep red, burnt orange, and gold as summer merges into fall.
Hakonechloa macra ‘All Gold’ lights up the walkway and softens its edge. Design and photo courtesy of Robin Parsons
Sedges (Carex)
Sedges are lower-growing evergreen or deciduous grass-like plants that are
attractive in drifts or edging a walkway. They tend to look best with
occasional water. Sun and shade requirements vary by species.
Many designers use the fine-textured evergreen Carex testacea, which has dense, arching tufts of coppery orange foliage. Bowles’ Golden Sedge (Carex elata ‘Aurea’) is another favorite. Although this deciduous, clump-forming selection thrives in sun or light shade, its chartreuse foliage really brightens up areas with low light.
Several varieties of the species Carex oshimensis are popular with designers. Designer Lisa Bauer favors ‘Everillo’ because the winter burn that afflicts other sedges is absent. Its lime green leaves are stiff but flexible and look great in mass plantings. Other varieties of this species that are specified by designers include ‘Evergold’ with dark green and butter yellow variegated foliage and ‘Everest’, whose deep green blades have snowy white margins.
The orange-hued New Zealand native Carex testacea borders the wall, while the upright maiden grass (Miscanthus sinensis ‘Morning Light’) dots the landscape beyond. Design and photo courtesy of Katie Weber
Small Wonders
Edging a garden bed with small grasses gives a finishing touch to your
composition. Alternatively, massing smaller selections beneath a specimen
tree showcases the tree without detracting from it.
The truly black Black Mondo Grass (Ophiopogon planiscapus ‘Nigrescens’) is eye catching in any landscape. Another, and quite different, mondo grass, Ophiopogon ‘Pam Harper’, is favored by Vancouver, WA, designer Vanessa Nagel, who likes to mingle this green and white variegated selection with groundcovers and short perennials to create a ground-covering matrix beneath shrubs.
Several fine-foliaged fescues are good candidates for drier areas. Among these are Festuca roemeri, an Oregon native, and West Coast native Festuca rubra ‘Patrick’s Point’, an exceptionally blue variety that tops out at 9 inches tall.
For dry shade and low water, try the chartreuse Luzula sylvatica ‘Aurea’. Its green cousin, Luzula pilosa ‘Igel’, which reaches 6 inches tall, is happier in a woodland setting with rich, moist, well-drained soil.
At the Chihuly Gardens in Seattle, the black mondo grass in this composition sets off a Chihuly sculpture. Photo courtesy of Janine Anderson
The Best of the Rest
At the top of the list in this category has to be Variegated Purple Moor
Grass (Molinia caerulea ssp. caerulea ‘Variegata’). This
tidy variegated clumper reaches 3 by 3 feet once the flowers and seed heads
emerge in late summer. It is effective rimming a border or in a drift.
Provide summer water during dry spells and cut to the ground in the fall
after it turns yellow.
Karl Foerster Feather Reed Grass (Calamagrostis x acutiflora ‘Karl Foerster’) adds a strong vertical element to your landscape. Although the foliage reaches only two feet, its feathery flower stalks, which emerge in June, grow to 6 feet tall. It enjoys a sunny location and needs summer water only until established. As with other deciduous grasses, ‘Karl Foerster’ should be cut to the ground in late winter.
Two worthy evergreen selections of a more diminutive nature include Autumn Moor Grass (Sesleria autumnalis) and New Zealand Red Hook Sedge ( Uncinia rubra ‘Belinda’s Find’). Maxing out at under two feet tall and wide, Autumn Moor Grass has bright green narrow leaves and silvery white flower stalks through fall and winter. It needs little water once established and just a bit of fussing in the spring to rake out the old foliage. ‘Belinda’s Find’, which reaches 12 inches tall, has arching bronzy red leaves and prefers cool, moist conditions.
One of the many non-grass grasses, Astelia nivicola ‘Red Gem’ is a well-behaved stunner in the landscape. This evergreen lily relative has arching, red tinged and silver sword-shaped foliage that reaches about 2 by 2 feet. Avoid hot spots and full sun and provide rich, well-drained soil.
Tall Feather Reed Grass encloses sitting area and buffers nearby park. Other grasses seen here are Bowles’ Golden Sedge (Carex elata ‘Aurea’) and Black Mondo Grass (Ophiopogon planiscapus ‘Nigrescens’). Design by Janine Anderson; photo ©Doreen Wynja.
Caveats and Conclusions
Gardening is a process of trial and error. Most landscape designers love
plants and like to experiment with unfamiliar plants and try new
compositions. They develop a mental database of which plants work, as well
as those they want to steer clear of.
Designers avoid grasses they have found to self-sow. Few things are more frustrating than a glorious garden being invaded by scores of unwanted seedlings. Grasses you might see in your local garden center that have a reputation for self-sowing include Carex comans ‘Frosted Curls’ and Mexican Feather Reed Grass (Stipa tenuissima).
Feelings about some grasses are mixed. One designer raves about Pheasant’s Tail Grass (Anemanthele lessoniana) while another has found it seeds everywhere and will not use it. For the same reason, the jury is conflicted about other grasses as well, including Carex flacca ‘Blue Zinger’, Calamagrostis brachytricha, Luzula sylvatica ‘Marginata’, Molinia caerulea ssp. arundinacea ‘Skyracer’, and Stipa gigantea. Although it doesn’t self-sow, the rhizomes of Carex morrowii ‘Ice Dance’ can expand it beyond its intended territory, yet it might be perfect in a woodland garden that stays a little on the dry side.
When in doubt, consult a landscape designer about the best grasses for your garden, or better yet, enlist a landscape designer to help you create compositions that you will enjoy now and for years to come.