What “drought-tolerant” really means for grasses
Most ornamental grasses sold for dry gardens are drought-tolerant only once they are established. A newly planted grass has a small root system and needs regular watering through its first growing season. After that, many of the plants below get by on far less water than typical border perennials.
Two conditions matter more than almost anything else: full sun (roughly six or more hours a day) and well-drained soil. Sun-loving grasses that sit in soggy ground over winter tend to rot at the crown, which is a more common cause of loss than dry weather.
Grasses also fall into two groups that affect when they look their best and when you prune them (compared in detail in warm-season vs cool-season ornamental grasses):
- Cool-season grasses (blue fescue is the classic example) start growing early, often stay evergreen or semi-evergreen, and may look tired in the worst summer heat.
- Warm-season grasses (little bluestem, switchgrass, muhly grass, fountain grass) grow strongly through summer, flower in late summer or fall, and go dormant in winter.
Grasses that handle dry, sunny sites
Hardiness zones and heights vary by cultivar and by source, so treat the figures here as rough guides and check the plant tag for your variety.
- Blue fescue (Festuca glauca): a small, tidy, blue mound, usually under a foot tall. Good for edging, rock gardens and containers. It prefers drier conditions and sharp drainage. If yours are dying out in the middle, see why blue fescue dies in the center and how to fix it.
- Little bluestem (Schizachyrium scoparium): a native prairie grass with blue-green summer foliage that turns coppery and red in fall. It does well in lean, dry soil. Cultivars differ a lot in height and color, covered in little bluestem varieties and the best cultivars for garden color.
- Pink muhly grass (Muhlenbergia capillaris): fine foliage topped by a pink haze of flowers in fall. It becomes very drought-tolerant once established. See how to grow pink muhly grass for the best fall bloom.
- Mexican feather grass (Stipa or Nassella tenuissima): a fine-textured, silky grass that likes sun and dry soil. It can self-seed freely and is regarded as a weed risk in some regions, so check local guidance first.
- Switchgrass (Panicum virgatum): an upright native that tolerates a range of soils. Cultivars such as ‘Heavy Metal’, ‘Northwind’ and ‘Shenandoah’ stay fairly compact and offer blue or burgundy tones.
- Dwarf fountain grass (Pennisetum alopecuroides ‘Hameln’): bottlebrush plumes and gold fall color at a manageable size. Provide well-drained soil.
- Blue grama (Bouteloua gracilis) and sideoats grama (B. curtipendula): low to medium native grasses that tolerate drought and a wide range of soils.
- Prairie dropseed (Sporobolus heterolepis): a fine-textured native mound with golden fall color.
- Feather reed grass (Calamagrostis x acutiflora ‘Karl Foerster’): upright and well behaved. It is notably adaptable, including to clay, so it suits average conditions better than the very driest sites.
Planting and establishing in dry ground
- Choose a sunny spot with good drainage. In heavy clay, consider a raised bed or mound, or work in grit to improve drainage.
- Soak the plant in a bucket before planting and, if it is pot-bound, loosen or lightly score the roots.
- Plant at the same depth as it was in the pot, with the crown level with the soil surface. Too deep invites rot; too high dries the plant out.
- Space for mature size. A common rule is to allow roughly the plant’s mature spread between plants.
- Water deeply but not often while it establishes, then taper off. Deep, infrequent watering encourages deeper roots.
- Mulch lightly. Gravel or a thin organic layer works, kept clear of the crown. In a gravel bed, see grasses to grow in a gravel garden.
Planting time depends on the type. Warm-season grasses generally establish best when planted in spring; cool-season grasses can be planted in spring or early fall.
Care: cutting back, dividing and feeding
- Cutting back: Leave the foliage and seed heads through winter for interest and for birds, then cut back to a few inches above the ground in late winter or early spring, before new growth starts. Evergreen types such as blue fescue and sedges are usually combed out with gloved hands rather than cut hard.
- Dividing: Many clumping grasses benefit from division every three to four years, or sooner if the center thins out. Divide warm-season grasses in early spring and cool-season grasses in early fall or spring.
- Feeding: Most need little or none. Rich soil and extra nitrogen tend to produce floppy, weak growth, particularly in grasses like little bluestem.
Grasses to avoid or use with care
Some popular ornamental grasses spread by seed into natural areas. Extension services in several regions flag pampas grass, Japanese blood grass, giant reed, and some forms of fountain grass and maiden grass (Miscanthus sinensis) as problems locally. Whether a grass is a problem depends on where you live, so check your state or regional invasive plant list before buying, and prefer sterile or clump-forming cultivars and native alternatives where you can.
Common questions
Is there an ornamental grass that does well in shade? A few do, but they are not the dry-sun group. Japanese forest grass (Hakonechloa), some sedges (Carex) and northern sea oats are commonly recommended for part shade, and most want more moisture than the grasses above.
What grasses grow in wet soil? Many sedges and rushes tolerate moist or wet ground, as do some switchgrass cultivars and Korean feather reed grass in moist spots. These are the opposite of the dry-garden plants, so keep them in separate parts of the garden.
What ornamental grasses suit zone 6b? Hardiness varies by cultivar, but little bluestem, switchgrass, feather reed grass, prairie dropseed, blue fescue and many dwarf fountain grasses are commonly listed as hardy in zones that include 6b. Check the tag for your specific cultivar, and see good ornamental grasses for Zone 6B for a fuller list.
Where to go next
- Planning a stone or gravel bed? Read about grasses for a gravel garden and how to lay pebbles in a garden.
- Gardening near the sea? See ornamental beach grasses for coastal gardens.
- Mild-winter regions: Australian and New Zealand grasses for mild climates.
- Choosing for a front bed: good ornamental grasses for the front of your house.