What zones 5 and 6 mean for grasses
USDA hardiness zones are based on the average coldest winter temperature. Zone 5 runs from about -20°F to -10°F, and zone 6 from about -10°F to 0°F. Zone 6b is the colder half of zone 6, roughly -5°F to 0°F. These are averages, so an unusually harsh winter can go below them.
For grasses, the zone on the plant tag is the main filter, but it is not the only one. Wet winter soil, exposed sites and young plants can all cause losses in plants that are technically hardy. Most of the grasses below are reliable in both zones, and the few that are borderline in zone 5 are flagged.
If you garden somewhere colder or warmer, these pages cover other climates: cold-hardy grasses for zones 3 and 4, grasses for zones 7 and 8, and heat-loving grasses for zones 9 and 10.
Cool-season vs. warm-season grasses
Grasses fall into two groups, and the difference affects when they look good and when to cut them back. Our guide to warm-season vs cool-season grasses has full lists.
- Cool-season grasses (feather reed grass, blue fescue, blue oat grass, tufted hair grass) start growing early in spring and are at their best in spring and early summer.
- Warm-season grasses (switchgrass, little bluestem, Miscanthus, fountain grass, pink muhly) wake up later in spring and peak from late summer through fall.
Mixing both gives a longer season of interest. Warm-season grasses are also the ones people most often expect to be “late,” so a clump that looks dormant in May is usually fine.
Reliable grasses for zone 5
For a shorter answer focused on zone 5 alone, see what ornamental grasses are suitable for zone 5.
Tall grasses (about 4 feet and up)
- ‘Karl Foerster’ feather reed grass (Calamagrostis × acutiflora): narrow, upright, with wheat-colored plumes in early summer. It is commonly rated hardy in zones 4 or 5 through 9, tolerates heavier or damper soil than many grasses, and holds its shape well into winter.
- Maiden grass (Miscanthus sinensis, such as ‘Gracillimus’ or the more compact ‘Adagio’): a fountain-shaped clump with plumes that age to silver or buff. Heights vary a lot by cultivar, from about 3 to 4 feet to well over 6 feet.
- Switchgrass (Panicum virgatum, such as ‘Shenandoah’ or ‘Northwind’): a North American native with airy flower heads and upright to arching habit. Cultivars range from roughly 3 to 6 feet.
- Big bluestem and Indian grass: tall prairie natives that suit larger, sunnier, more naturalistic plantings. See our guide to Midwest and native prairie grasses.
Medium grasses (about 2 to 3 feet)
- ‘Hameln’ dwarf fountain grass (Pennisetum alopecuroides): soft, bottlebrush plumes and gold fall color. Usually rated for zones 5 to 9.
- Little bluestem (Schizachyrium scoparium): blue-green summer foliage turning copper, orange and red in fall. Tolerant of lean soil and drought once established.
- Prairie dropseed (Sporobolus heterolepis): a fine-textured mound with a distinctive scent when in bloom and orange-tan fall color.
Short grasses (under about 2 feet)
- Blue fescue (‘Elijah Blue’, ‘Boulder Blue’): tidy blue mounds, best in full sun and good drainage. It can be short-lived, often a few years, and may decline in hot, wet summers. See why blue fescue dies in the center.
- Blue oat grass (Helictotrichon sempervirens): steel-blue spiky foliage, also needs good drainage.
- Dwarf fountain grasses such as ‘Little Bunny’ for small beds and pots.
Adding zone 6 and 6b
Everything above generally works in zone 6. The extra winter warmth also opens up a few more options:
- Pink muhly grass (Muhlenbergia capillaris) is commonly listed for zones 6 to 9 (some sources say 5). It produces a pink haze in fall and is a favorite in full sun. In zone 6, a sunny, well-drained spot gives it the best chance. See how to grow pink muhly grass.
- Miscanthus and switchgrass cultivars that are only borderline in zone 5 are less of a gamble.
- Japanese blood grass and some sedges become easier, though see the invasive notes below for blood grass.
For a plant list written specifically for the colder half of zone 6, see good ornamental grasses for zone 6b.
Grasses for shade
Most ornamental grasses want at least six hours of sun, but a few handle shade (our guide to ornamental grasses for shade has more):
- Japanese forest grass (Hakonechloa macra): arching, golden or variegated, prefers moist but not soggy soil and part shade.
- Northern sea oats (Chasmanthium latifolium): a woodland native with dangling seed heads that tolerates light shade. It can self-seed freely.
- Sedges (Carex), such as Pennsylvania sedge, ‘Ice Dance’ and ‘Everillo’: grass-like, often evergreen or semi-evergreen, and good for part shade.
- Tufted hair grass (Deschampsia cespitosa): handles sun to part shade.
Red and burgundy perennial grasses
If you want red tones, look at foliage that colors up in fall rather than red all season (see also ornamental grasses for fall color):
- Little bluestem cultivars turn copper, orange and red.
- Switchgrass ‘Shenandoah’ has red-tipped foliage that deepens through summer.
- Big bluestem cultivars such as ‘Blackhawks’ turn burgundy-purple.
- Japanese blood grass ‘Red Baron’ is red from midsummer, but check local invasive-plant guidance first.
- Purple fountain grass (Pennisetum setaceum ‘Rubrum’) is burgundy all season but is typically hardy only to about zone 8, so it is grown as an annual in zones 5 and 6.
Are ornamental grasses invasive?
Most are not (see non-invasive ornamental grasses). Ornamental grasses are either clumping, which slowly widen but stay put, or running, which spread by rhizomes. Most garden grasses clump. Even so, a few cause problems:
- Miscanthus sinensis can self-seed and has become a problem in parts of the eastern United States. Sterile or lower-seeding cultivars are a safer choice, and local extension offices can tell you if it is a concern in your area.
- Japanese blood grass is related to cogon grass (Imperata cylindrica), a serious weed in the Southeast. Some sources advise skipping it in that region.
- Ribbon grass (Phalaris arundinacea var. picta) spreads aggressively by rhizomes.
- Mexican feather grass self-seeds and is flagged as a problem in some western regions.
- Fountain grass (Pennisetum setaceum) is invasive in some warm regions, though it is not winter hardy in zones 5 and 6.
Rules of thumb: check your state or county invasive plant list before buying, prefer clumping and native species, and cut seed heads off before they scatter if you are unsure.
Where and when to plant
Choose a spot with full sun (at least six hours) and well-drained soil for most grasses. Wet soil in winter hurts many of them more than cold does. Give them room for their mature width, since crowding leads to flopping and mildew.
For timing, spring is the safest planting time in zones 5 and 6, especially for warm-season grasses. Early fall also works for many, as long as the roots have a few weeks to settle before the ground freezes. Very late planting leaves roots with less time to establish and raises the risk of winter loss, so water well and mulch if you plant late. Water regularly through the first year or two; after that, most are drought tolerant.
Do perennial grasses come back every year?
Yes, if the plant is hardy in your zone. A perennial grass dies back to the crown in winter (or stays semi-evergreen) and regrows from the same roots in spring. Grasses sold as annuals, or tender ones like purple fountain grass, will not survive a zone 5 or 6 winter.
Leave the dry foliage standing over winter. It gives structure, protects the crown and feeds birds. In late winter or early spring, before new growth appears, cut deciduous grasses back to a few inches above the ground. Evergreen types, such as many sedges and blue fescue, only need a light tidy-up. Large clumps that die out in the center can be divided in spring.
Tall grasses for pots
Tall grasses can work in large containers, but winter survival is lower in pots because roots are less insulated. A tall pot-friendly list is in our guide to tall grasses for pots. If you want to start from seed, see where to find ornamental grass seeds.