If perennials are the color in a xeriscape, ornamental grasses are the architecture. They bring movement, sound and texture, and they stand tawny and sculptural through winter long after the flowers quit. The best drought-tolerant grasses for Western yards are natives like blue grama, little bluestem, sideoats grama and prairie dropseed, plus a few proven imports like Karl Foerster feather reed grass and blue oat grass. Below are 10 worth planting, with zones, water, size and care, and clear caveats on the two that can cause trouble.
One rule from CSU Extension's ornamental grasses fact sheet is worth knowing up front: among the natives, the taller the grass, the more water it needs, and many grasses from moist parts of Asia and Europe need ample water. That's why the short prairie and steppe grasses dominate this list.
The 10 at a glance
| Grass | Zones | Water | Height | Season of interest |
|---|---|---|---|---|
| Blue grama | 3–10 | Very low | 12–24 in | Summer–winter |
| Little bluestem | 3–9 | Very low | 24–48 in | Fall–winter color |
| Sideoats grama | 4–9 | Very low | 18–30 in | Summer–fall |
| Prairie dropseed | 3–9 | Very low | 18–36 in | Late summer–fall |
| Undaunted® ruby muhly | 5–9 | Very low | 24–36 in | Fall |
| Blue oat grass | 4–8 | Low | 18–30 in (plumes to 36 in) | Evergreen |
| Karl Foerster feather reed grass | 4–9 | Low | 36–60 in | June–February |
| Switchgrass | 4–9 | Low–moderate | 48–72 in | Summer–winter |
| Fountain grass | 5–9 | Moderate | 18–30 in | Late summer–fall |
| Mexican feather grass | 7–10 | Very low | 12–24 in | Summer (use with caution) |
The natives: toughest of the tough
1. Blue grama (Bouteloua gracilis)
Zones 3–10 · Water Very low · Size 12–24 in · Interest "Eyelash" seed heads summer into winter
Colorado's state grass and a Great Plains icon, with horizontal seed heads that look like eyelashes. Blue grama is a warm-season bunchgrass that the Lady Bird Johnson Wildflower Center calls a dominant grass in dry shortgrass prairies, commonly planted with buffalograss as turf. Use 'Blonde Ambition' as a specimen, or mow the species as a low-water lawn.
Care tip: It greens up late (May on the Front Range); don't mistake spring dormancy for death.
2. Little bluestem (Schizachyrium scoparium)
Zones 3–9 · Water Very low · Size 24–48 in · Interest Blue-green summer, copper-red fall and winter
Steel-blue summer blades that turn copper-red in fall and hold that color all winter. Little bluestem is upright, tidy and spectacular in drifts. 'The Blues' and 'Standing Ovation' are good compact selections.
Care tip: In rich or watered soil it flops; keep it lean and dry.
3. Sideoats grama (Bouteloua curtipendula)
Zones 4–9 · Water Very low · Size 18–30 in · Interest Oat-like seeds dangling from one side of the stem, summer to fall
Blue grama's taller cousin, with small seed "oats" hanging along one side of each arching stem. The Missouri Botanical Garden rates sideoats grama zones 4–9 with dry-to-medium water. It pairs well with penstemon and blanket flower.
Care tip: Cut back to 3 or 4 inches in early spring.
4. Prairie dropseed (Sporobolus heterolepis)
Zones 3–9 · Water Very low · Size 18–36 in · Interest Fine fountain of leaves; fragrant late-summer flowers
Elegant, hair-fine mounds that turn orange in fall. The late-summer flowers smell faintly of popcorn or cilantro. Prairie dropseed is slow to establish but long-lived.
Care tip: Buy larger plants or be patient; it takes two or three seasons to size up.
5. Undaunted® ruby muhly (Muhlenbergia reverchonii 'PUND01S')
Zones 5–9 · Water Very low · Size 24–36 in · Interest Ruby-pink flower haze in fall
A Plant Select introduction that brings the pink "cloud" look of Gulf muhly to colder, drier yards. The Missouri Botanical Garden rates the species zones 5–9 with dry-to-medium water.
Care tip: Site it where low fall sun shines through the flowers; that's when it glows.
The adapted classics
6. Blue oat grass (Helictotrichon sempervirens)
Zones 4–8 · Water Low · Size 18–30 in, plumes to 36 in · Interest Evergreen steel-blue foliage
A steely-blue evergreen porcupine of a plant, and the best cool-toned accent in the dry palette. Blue oat grass is a cool-season grass rated zones 4–8.
Care tip: Don't cut it to the ground. Comb out dead leaves with gloved fingers in spring.
7. Karl Foerster feather reed grass (Calamagrostis × acutiflora 'Karl Foerster')
Zones 4–9 · Water Low · Size 36–60 in · Interest Wheat-colored plumes from June into winter
The vertical exclamation point. CSU Extension notes its flower spikes form in May to June, turn golden, then bleach tan and persist into winter. Feather reed grass is sterile, so it never self-sows. The variegated 'Overdam' (in the photo at top) is a shorter sister.
Care tip: Give it a deep soak every week or two in summer heat; it's a cool-season grass and goes brown faster than the natives in drought.
8. Switchgrass (Panicum virgatum)
Zones 4–9 · Water Low to moderate · Size 4–6 ft · Interest Airy seed clouds, fall color, winter structure
Four to six feet of vertical presence with airy seed clouds. 'Northwind' stays rigidly upright; 'Shenandoah' turns wine-red. It's a tallgrass-prairie native, and several cultivars are rated for medium-to-wet soil by the Missouri Botanical Garden, so treat switchgrass as a "low to moderate" plant: put it on the wetter end of your drip layout, not the driest corner.
Care tip: Cut it back in early spring before new growth; it's one of the last grasses to green up.
Two to use with caution
9. Fountain grass (Pennisetum alopecuroides)
Zones 5–9 · Water Moderate · Size 18–30 in · Interest Foxtail plumes late summer to fall
Fluffy foxtail plumes over graceful mounds, the grass most people picture. It needs noticeably more water than the others here (the Missouri Botanical Garden lists medium-to-wet soil for common cultivars), so plant it only in a moderate-water zone. Don't confuse it with purple or crimson fountain grass (Pennisetum setaceum), which is invasive in the desert Southwest and Southern California and should be avoided there.
Care tip: Cut back in early spring; mulch the crown in zone 5.
10. Mexican feather grass (Nassella tenuissima)
Zones 7–10 · Water Very low · Size 12–24 in · Interest Hair-fine blond texture that moves in any breeze
Beautiful motion, real downsides. The Missouri Botanical Garden rates it zones 7–10, colder than it's often sold for, and it reseeds heavily and is considered invasive in parts of California. In most places, blue grama or prairie dropseed give a similar fine texture without the risk.
Care tip: If you grow it, cut the seed heads before they ripen in midsummer.
Using grasses well
- Mass them. A single grass looks stranded; drifts of 5 to 9 read as landscape.
- Backlight them. Plant grasses where morning or evening sun shines through the plumes.
- Pair with bold companions. Fine grass texture makes yucca, agave and broad-leaved perennials stand out.
- Leave them standing all winter. CSU notes grasses are commonly left standing until spring for winter structure. Cut back to a few inches in early spring before new growth. On public or commercial sites, remove dry foliage earlier, since it's combustible.
- Plant in spring. CSU recommends spring planting, with container-grown grasses planted no later than a month before first frost.
From our installs
On the Front Range, the natives (blue grama, little bluestem, sideoats grama, prairie dropseed) are the grasses we plant most, because they handle clay, hail and a dry winter with no fuss. The cool-season imports, Karl Foerster and blue oat grass, look good earlier in spring but need an occasional deep summer soak. The most common grass problem we see is too much water and fertilizer, which makes little bluestem and switchgrass flop open. We water new grasses deeply once or twice a week the first summer, then taper off. A late-spring hailstorm can shred new growth; grasses recover within a few weeks. (Xeris Landscaping is owned by Xeriscaping.com's founder.)
Frequently asked questions
When should I cut back ornamental grasses?
In early spring, just before new growth starts. Leave them standing through winter for structure and wildlife cover.
Which ornamental grasses need the least water?
Blue grama, little bluestem, sideoats grama, prairie dropseed and ruby muhly. Taller grasses like switchgrass and imports like fountain grass need more.
Do ornamental grasses spread?
Most on this list are clumping bunchgrasses that stay put. Mexican feather grass reseeds heavily, and blue grama can fill in when mowed as a lawn.
What grass works as a lawn alternative?
Blue grama and buffalograss can be mowed as a low-water lawn. See buffalograss and blue grama lawns and the upcoming lawn alternatives guide.
For design ideas that use grasses well, see xeriscaping ideas and inspiration and rock garden design. In Colorado's southern Front Range, xeriscaping in Colorado Springs covers local conditions; in Idaho, see xeriscaping in Boise.
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