Why ornamental grasses work in a landscape
Ornamental grasses add things that many shrubs and perennials cannot: fine texture, vertical lines, and movement in even a light breeze. Their foliage and seed heads also catch low autumn and winter sun, and many hold their shape well into winter. Because most are grown as clumps that are cut back once a year, they are often chosen to reduce routine upkeep, though the amount of care varies by species.
They suit many settings, including small urban lots, large suburban yards, borders, containers and screens. The key is choosing the right grass for the job, rather than treating “ornamental grass” as one plant. For an overview of the main groups, see types of ornamental grasses.
Think in layers: low, middle and tall
A simple way to plan is by height, much like planting a perennial border.
- Front of the border (about 6 to 18 inches): blue fescue, mondo grass, sedges (Carex) and Hakone grass. See small ornamental grasses for borders and edging.
- Middle layer (about 2 to 4 feet): dwarf fountain grasses such as ‘Hameln’, little bluestem, compact switchgrasses and pink muhly grass in warmer zones.
- Upper layer (4 feet and taller): feather reed grass, larger Miscanthus and taller switchgrasses. These work as backdrops, screens or standalone accents. See tall ornamental grasses for privacy screens and fence lines.
Listed heights usually refer to foliage, and flower stems can add a foot or more, so check both numbers before planting.
Architectural grasses and structure
“Architectural” grasses are those with a strong, definite form: upright columns such as feather reed grass ‘Karl Foerster’, fountain-shaped clumps, or broad, vase-shaped Miscanthus. These plants act like sculpture in the garden. Use them where you want a clear shape, such as beside an entry, at a bed corner or as a single feature. Our guide to specimen grasses and focal points goes into this further, and modern and minimalist planting shows how to repeat these forms for a clean look.
Cool-season and warm-season grasses
This distinction, explained fully in warm-season vs cool-season ornamental grasses, affects when a grass looks its best and when you should cut it back.
- Cool-season grasses (for example blue fescue and feather reed grass) start growing early in spring, and some stay semi-evergreen.
- Warm-season grasses (for example switchgrass, Miscanthus and pink muhly) wait for warm soil, then peak in late summer and fall.
Warm-season grasses are typically cut back in late winter or early spring, before new growth starts. Leaving them standing through winter provides interest and shelter for wildlife.
Pairing grasses with shrubs and perennials
Grasses soften the rounded shapes of foundation shrubs and give flowering plants a fine-textured backdrop. A few reliable ideas:
- Contrast fine, narrow blades with bold, broad leaves such as hostas or hydrangeas. See pairing grasses with hydrangeas and flowering shrubs.
- Combine with sun-loving perennials such as coneflower and sedum. See perennials to plant with ornamental grasses.
- Use evergreen shrubs for winter structure and grasses for seasonal movement. If you are unsure how woody plants and grasses differ, read the difference between shrubs and grasses.
Group plants in drifts
A common design guideline is the 3-5-7 rule: plant in odd numbers so groupings look natural. Repeating the same grass at several points along a bed ties the planting together. One large plant can also work well as a focal point, so use judgment based on the size of your space. Another framework, the 70/30 rule, balances reliable structure plants with seasonal accents.
Match the grass to sun, shade and soil
Most ornamental grasses prefer full sun and well-drained soil. For damp ground, see ornamental grasses for wet areas. For shade, sedges, Hakone grass and mondo grass are common choices. See ornamental grasses that grow in shade. For containers, see growing ornamental grasses in containers.
Routine care
Most clumping grasses need little more than an annual cut-back, with occasional division if the center of the clump thins. If you want the easiest options, see the best low-maintenance ornamental grass. For seasonal color, see ornamental grasses for fall.
Grasses to be careful with
Some ornamental grasses self-seed or spread aggressively in certain regions. Miscanthus sinensis and some fountain grasses are examples that are considered invasive in parts of North America. Check your local extension service or invasive plant list before buying, and look for sterile or non-seeding cultivars where relevant. Running bamboo is another plant to approach with caution.