Masses of Grass: Planting Large Groupings Of Ornamental Grasses

by David Salman

Chinese maiden hair with lavender
Chinese Maiden Hair Grass with a mass planting of Lavender

Ornamental grasses are some of our very best garden plants. They're low care perennials with a big impact on the look of our landscapes. With their fine-textured foliage, attractive flowers and seed heads, graceful movement in the breeze along with extended fall and winter beauty, they give us a remarkable visual contrast with flowering perennials, shrubs and other garden plants.

But ornamental grasses look best when used in larger numbers. How often do you see a prairie or meadow with just one grass plant?

Follow David Salman's recommendations for gorgeous mass plantings with Ornamental Grass. With these tips, you can create a breathtaking garden that is low maintenance, yet still has a major visual impact. 

Ornamental Grass Garden with Naseella and Little Bluestem
Ornamental Grass Garden with Nassella tenuissima and Little Bluestem grasses combine for an informal planting style at the Denver Botanic Garden in autumn.

Massing: Formal & Geometric, or Informal & Natural?

Grasses are accustomed to growing in groups, which in gardening terminology is referred to as "massing." Massing can also refer to planting large numbers of grass plants (without other non-grass plants) to create dramatic geometric 3-D patterns. This can be accomplished in both formal and informal ways. Grasses lend themselves to being planted in pleasing geometric patterns or simply grouped together in less formal arrangements.

Ornamental Grass With Blonde Ambiation Grass
Blonde Ambition Blue Grama Grass works for formal plantings as shown in this municipal landscape planting in New Mexico.

Designing Formal, Geometric Plantings With Grass

For structured plantings, follow these key guidelines:
  • Use long-lived species and cultivars. Short-lived varieties like blue Festuca ovina cultivars and Nassella (Silky Thread Grass) are not good choices.
  • Use grasses that don't reseed themselves to any large extent. Otherwise, they quickly fill in between the original plants and destroy the planting pattern.
  • Use grasses that grow as clumps, not ones that spread to create large mats via stolons (arching stems that push from the center of the grass and develop roots at the nodes where they touch the ground). Leymus arenarius and related species are "runners." These grasses are best used to cover slopes, beaches, and other larger areas.
  • Stick with one grass variety to accentuate the visual impact by creating uniformity of the planting. However, two or three types of grasses can be combined by planting differently-sized grasses in geometric grid patterns that are placed side by side.
Pink Flamingo Mulhy Grass with Blonde Ambition Blue Grama Grass
Blonde Ambition Blue Grama Grass planted with Pink Flamingo Mulhy Grass perfectly play off each other with their attractive foliage, and bright plumes.

Foer example, I've seen formal plantings of Nassella tenuissima (Silky Thread Grass) that for a couple of growing seasons, looked really nice. But Nassella is not a long-lived species, which for a geometric mass planting, is not good. By the third year, some of the original plants had died and there were a lot of volunteer seedlings that had filled in between the original plants. Thus the geometric unity of the design was ruined by gaps in the original grid and in-fill from volunteer seedlings.

Recommended Long-Lived, Low-Reseeding Grasses For Formal, Geometric Groupings:


Caradonna Sage with Magnus Purple Coneflower
Caradonna Sage
(Salvia) and Magnus Purple Coneflowercombine beautifully with Ruby Muhly Grass in this Sonoma, CA garden.

Designing Informal, Natural Plantings With Grass

For informal plantings, there is much more latitude. Informal designs allow the gardener to use a variety of grass species and cultivars, that are grouped in non-geometric patterns. Informal plantings accommodate shorter lived types, varieties that re-seed themselves and stoloniferous types along the edges. The gardener needs to do some "editing" each spring to thin out volunteer seedlings, so the planting doesn't become too dense and too much of a scrambled mixture.

There are so many possible combinations that will beautify the garden. But be sure that you used odd numbers of each grass (3,5,7) planted together. Mix the groups of one type with groups of other types. One each, of many different kinds of grass creates a hodge-podge design with no visual focal points on which the eye can rest. Use shorter types masses around groups of larger growers. It is also permissible to include groupings of larger growing perennial flowers to provide color and contrast. Prairie species of flowering perennials are always a good choice.

Mulenbergia White Cloud
White Cloud Muhly Grass
 is a hard-to-find ornamental grass which thrives in both heat and humidity. This perennial grass is perfect for plantings of atleast three.

Recommended Grasses For Informal, Naturalizing Plantings:

Create habitat for butterfly/moth caterpillars and seed-eating songbirds by using native species and cultivars. Look for these grass species:


Shop Ornamental Grass

  1. Blue Whiskers Fescue Grass

    Eye-catching Festuca glauca ‚Blue Whiskers‚ PP#29,200 (Fescue Grass) is a colorful standout you will want in your garden. Taller, brighter blue, and with striking long le...

    Learn More
    Blue Whiskers Fescue Grass Blue Whiskers Fescue Grass Festuca glauca 'Blue Whiskers' PP#29,200
    $13.99
    Per Plant - 5" Deep Pot
    Eye-catching Festuca glauca 'Blue Whiskers' PP#29,200 (Fescue Grass) is a colorful standout you will want in your garden. Taller, brighter blue, and with striking long leaves, its silvery hue gives your garden textural contrast. In early to mid-summer yellow-green flowers emerge just above the foliage and will turn tan as they age. This lovely evergreen grass will provide beautiful winter interest. It is low-maintenance, waterwise, and deer resistant for easy gardening.
  2. Undaunted® Girl Next Door Deer Grass

    Muhlenbergia rigens ‚Undaunted® Girl Next Door‚ USPP (Deer Grass) is the most cold-hardy form of Muhlenbergia, a xeric Southwestern-native favored for garden and landsca...

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    Undaunted® Girl Next Door Deer Grass Undaunted&reg Girl Next Door Deer Grass Muhlenbergia rigens Undaunted® Girl Next Door
    $14.99
    Per Plant - 5" Deep Pot
    Muhlenbergia rigens 'Undaunted® Girl Next Door' USPP (Deer Grass) is the most cold-hardy form of Muhlenbergia, a xeric Southwestern-native favored for garden and landscape design. Despite its common name, is deer resistant. This perennial grows with a graceful mound of sage-green foliage, and sends up fireworks of long-lasting tawny plumes that capture the light and wave in the breeze. Add a vibrant airy texture to complement summer flowers and light up a sunny, dry planting. A High Country Gardens exclusive.
  3. Karl Foerster Feather Reed Grass, Calamagrostis acutiflora Karl Foerster

    The world‚s most popular ornamental grass, Calamagrostis acutiflora ‚Karl Foerster‚ (Feather Reed Grass) has a strong upright habit and blooms with showy flowers th...

    Learn More
    Karl Foerster Feather Reed Grass Karl Foerster Feather Reed Grass Calamagrostis acutiflora Karl Foerster
    As low as $14.99 Sale $13.49
    Per Plant - 5" Deep Pot
    The world's most popular ornamental grass, Calamagrostis acutiflora 'Karl Foerster' (Feather Reed Grass) has a strong upright habit and blooms with showy flowers that ripen to tawny seed heads that decorate the plant through the fall and winter months.
  4. Muhlenbergia reverchonii, Undaunted Ruby Muhly Grass

    Muhlenbergia reverchonii ‚Undaunted® Ruby‚ (Muhly Grass) has an impressive late summer display of see-through amber-pink flower spikes. This is the one Muhly grass wi...

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    Undaunted® Ruby Muhly Grass Undaunted® Ruby Muhly Grass Muhlenbergia reverchonii PUND01S
    As low as $12.99
    Per Plant - 5" Deep Pot
    Muhlenbergia reverchonii 'Undaunted® Ruby' (Muhly Grass) has an impressive late summer display of see-through amber-pink flower spikes. This is the one Muhly grass with showy pink flowering plumes that can be grown in USDA zones 5 to 9. A High Country Gardens Introduction. Plant Select. Drought resistant/drought tolerant plant (xeric).
  5. Siskiyou Blue Idaho Fescue Grass, Festuca idahoensis Siskiyou Blue

    This is a new selection of the native Idaho Fescue, notable for its enticing spruce-blue foliage. The thin leaves are much longer than the more familiar Festuca glauca, giving Festuc...

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    Siskiyou Blue Fescue Grass Siskiyou Blue Idaho Fescue Grass Festuca idahoensis Siskiyou Blue
    As low as $12.99 Sale $11.69
    Per Plant - 5" Deep Pot
    This is a new selection of the native Idaho Fescue, notable for its enticing spruce-blue foliage. The thin leaves are much longer than the more familiar Festuca glauca, giving Festuca idahoensis 'Siskiyou Blue' a softer, more graceful look.
  6. Silky Thread Grass, Nassella tenuissima

    Nassella tenuissima (Silky Thread Grass) brings gossimer grace to any spot where it‚s planted. It blooms from late spring into late summer with plumes of silky flowers that sw...

    Learn More
    Silky Thread Grass Silky Thread Grass Nassella tenuissima
    As low as $11.99 Sale $10.79
    Per Plant - 5" Deep Pot
    Nassella tenuissima (Silky Thread Grass) brings gossimer grace to any spot where it's planted. It blooms from late spring into late summer with plumes of silky flowers that sway back and forth in the slightest breeze. Grow readily in most any soil with full to partial sun. Re-seeds itself readily. Not for sale in CA. Drought resistant/drought tolerant plant (xeric).
  7. Mini Oat Grass, Poa secunda v. juncifolia

    Poa secunda v. juncifolia (Mini Oat Grass) is a Western native grass with blue-green foliage. Seeds emerge on stiff foliage and open up to create pale feathery fronds. In summer dry ...

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    Mini Oat Grass (Poa) Mini Oat Grass Poa secunda v. juncifolia
    Sale Price I Save 10%
    $13.99 Sale $12.59
    Per Plant - 5" Deep Pot
    Poa secunda v. juncifolia (Mini Oat Grass) is a Western native grass with blue-green foliage. Seeds emerge on stiff foliage and open up to create pale feathery fronds. In summer dry season, grass matures to a warm gold hue. A highly resilient and drought-resistant grass that serves as a host plant for many butterflies, its upright habit and seed textures are a beautiful addition to waterwise landscapes, including high elevations.
  8. Carex appalachica, Appalachian Sedge, Photo Courtesy Of Hoffman Nursery

    Carex appalachica (Appalachian Sedge Grass) is a native grass-like plant with thin, fine-textured leaf blades. Appalachian Sedge is an outstanding choice for use as an attractive gra...

    Learn More
    Appalachian Sedge Grass Appalachian Sedge Carex appalachica
    As low as $11.99
    Per Plant - 5" Deep Pot
    Carex appalachica (Appalachian Sedge Grass) is a native grass-like plant with thin, fine-textured leaf blades. Appalachian Sedge is an outstanding choice for use as an attractive grassy groundcover for shade and heavy shade areas.

Text and Photos by Founder and Chief Horticulturist David Salman.

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