The short answer
In garden beds and borders, yes. Mixing cool-season and warm-season ornamental grasses is common and can give you a longer season of interest. In lawns the answer is usually no, apart from one well-known exception described below.
Mixing in garden beds
Ornamental grasses are planted as individual clumps, so each plant grows on its own schedule without competing with a neighbor for the same turf space. That makes mixing straightforward.
The benefits:
- Longer display. Cool-season grasses green up early and flower in early summer. Warm-season grasses take over in late summer and fall with plumes and fall color.
- More variety. Blue fescue, feather reed grass and tufted hair grass pair nicely with maiden grass, switchgrass and muhly grass.
- Less bare time. While warm-season clumps are still waking up in spring, the cool-season ones fill the gap.
Our guide to warm-season vs cool-season ornamental grasses lists plants in each group.
Care when you mix
The main difference is timing. When your bed has both types, keep a note of which is which:
- Cutting back: cool-season grasses go first, in very early spring, with some foliage left behind. Warm-season grasses can wait until late winter or spring, and are cut lower. See should all ornamental grasses be cut back in the spring.
- Dividing: cool-season grasses are usually divided in spring or early fall, and warm-season grasses from late spring to midsummer. See how to divide and transplant ornamental grasses.
- Planting: spring suits both groups. In fall, plant cool-season grasses early enough for roots to establish. See how hot is too hot to plant cool-season grass.
- Watering and feeding: needs vary more by species than by season, so group plants with similar needs together.
Design tips
- Plant in groups of three, five or seven of the same grass rather than single plants of many kinds, so the bed does not look cluttered.
- Place shorter cool-season grasses in front, or around the base of taller warm-season ones.
- Remember that warm-season clumps may look bare in early spring, so place them where a bit of gap is not an issue or fill with early bloomers.
For more combinations see types of ornamental grasses and these design principles for landscaping with ornamental grasses.
Mixing in lawns
Lawn advice is different. Cool-season lawn grasses (tall fescue, Kentucky bluegrass, perennial ryegrass) and warm-season lawn grasses (Bermudagrass, zoysia, St. Augustine) grow at different times, in different colors and textures. Mixed together, they tend to give a patchwork lawn, and one source advises against blending them for most home lawns.
The common exception is overseeding. In the South, many gardeners overseed a dormant Bermudagrass lawn with perennial ryegrass in fall for winter green, and the ryegrass fades as the Bermudagrass wakes up in spring. In the transition zone, where summers are too hot for cool-season grasses and winters are too cold for warm-season ones, some lawns combine the two types on purpose. If you have one of these lawns, regional lawn advice from a local extension service is more useful than general guidance.
Mixing in pastures
For grazing, mixing cool-season and warm-season grasses can provide forage over a longer part of the year. That is an agricultural setting and is separate from garden design.
Summary
- Garden beds: mixing is fine and often recommended.
- Home lawns: usually keep to one type, apart from winter overseeding of warm-season turf.
- Pastures: mixing is common to extend the grazing season.