How tall can a shade grass really get?
Honestly, not very tall. Most of the tallest ornamental grasses, such as miscanthus, pampas grass and switchgrass, are sun plants (see tall ornamental grasses for privacy screens). A University of Minnesota Extension guide to shady sites notes that the author knows of no truly tall grasses (4 feet or more) that grow in shade, and suggests tall perennials such as goat’s beard (Aruncus) and meadow rue (Thalictrum) for height instead.
In practice, “tall” for a shade or part-shade grass usually means about 3 to 5 feet, and mostly in part shade, where the plant still gets some direct sun. In deeper shade, expect plants to stay shorter than the size on the tag.
Best tall grasses for part shade
Korean feather reed grass (Calamagrostis brachytricha). Often listed at about 3 to 4 feet tall, with a fountain-like mound of foliage and pink plumes that fade to silver-tan in late summer and fall. Unlike many feather reed grasses, it is generally described as preferring part shade and soil that does not dry out. It is commonly listed as hardy in roughly zones 4 to 9.
Karl Foerster feather reed grass (Calamagrostis × acutiflora ‘Karl Foerster’). An upright grass that can reach around 4 to 5 feet and is often listed for sun to part shade. It stands more stiffly than most grasses, but it will bloom less and lean more as shade increases.
Northern sea oats (Chasmanthium latifolium). Typically 2 to 5 feet tall, with flat, dangling seed heads that start green and turn bronze or tan. It handles light to part shade, and in shade it generally stays shorter than it would in full sun. It can reseed freely and spread, so remove seed heads before they drop if you want to limit it.
Bottlebrush grass (Elymus hystrix). A native grass reaching about 2.5 to 4 feet including flower spikes, with bristly, bottlebrush-like seed heads in midsummer. It is often described as adaptable to dry or medium shade.
Tufted hair grass (Deschampsia cespitosa). Usually 2 to 4 feet tall when in flower, with airy, cloud-like flower heads. It prefers cool climates, moist soil and light to part shade, and in hot regions it needs afternoon shade.
What to expect as shade deepens
- Fewer and smaller flower heads. Many grasses bloom less in shade, so you may be growing them mainly for foliage.
- Floppier growth. Stems stretch toward the light and can lean or fall open.
- Shorter plants in deep shade. A grass labeled for sun to part shade often performs best with at least a few hours of direct sun.
If you can, choose a spot that gets morning sun and afternoon shade, which suits most of the plants above.
Tall grasses in pots
Pots can be a good way to add height to a shady patio, where you can control the soil and moisture. For sunnier pots, see good tall grasses for pots. Choose a large container with drainage holes and a good potting mix. Northern sea oats, Korean feather reed grass and shade-tolerant sedges can all be tried, but check hardiness: roots in pots are more exposed to cold than roots in the ground, so in cold climates a pot may need winter protection or a plant hardy a zone or two colder than your own.
Medium-height options such as Japanese forest grass look good in containers as well, though they will not add serious height.
Adding height without a tall grass
If you want vertical structure in the shade, mix grasses with taller non-grass plants. Goat’s beard and meadow rue are mentioned above. Ferns also add height with their arching fronds, and the larger ones, like ostrich fern, can stand well over 3 feet in moist soil. Grasses then supply fine texture around them.
Tall grasses to avoid in shade
These are great in sun, but usually disappoint in a shady bed:
- Pampas grass
- Giant miscanthus
- Big bluestem and Indian grass
- Fountain grass
Some miscanthus varieties tolerate part shade, but they lean and bloom less than in full sun.
Planting tips
- Plant in spring or early fall.
- Leave room for the mature width as well as the height.
- Water well through the first year, especially under trees where roots compete for moisture.
- Cut back old foliage in late winter or early spring.
For a wider look at grasses for low-light spots, see our main guide to ornamental grasses for shade and part shade. If your climate is cold, check which ornamental grasses suit zone 5.