Ornamental grasses come in a mix of sizes and offer texture, form, movement and seasonality to a garden.
When many gardeners hear the word grass, they think of lawn grasses that are mowed weekly. But there is a wide array of ornamental grasses that add almost year-round interest in the home landscape, and most are beginning to shine right now.
Ornamental grasses come in a very diverse mix of sizes, and the name ornamental grass includes true grasses, but also a wide range of plants that have a grass-like growth habit, including groundcover Mondo (Ophiopogon) and Monkey grass (Liriope) which are really in the lily family, to sedges and rushes that have a grass like appearance. Size of ornamental grasses can be low groundcovers up to the giant reed grass (Arundo donax) topping out at 20 feet tall. Width of grasses can be tall and narrow like feather reed grass (Calamagrostis) or wide and free flowing like pampas grass. Some grass species are native, and some are imported; some are annuals, and some are long-lived perennials.
Ornamental grasses offer texture, form, movement and seasonality to a garden. In the spring, the new foliage emerges which grows all season, followed by showy plumage in the fall. Once a killing frost occurs, true grasses turn a shade of tan or brown for the winter months. With the dried seed heads, they provide sound and movement in the garden, and can also be a source of food for birds. Prior to new growth in the spring, the old foliage should be cut as close to the ground as possible. Some gardeners cut their ornamental grasses down when they turn brown in the fall, but the sound, movement and form of the dried grasses adds a lot of winter interest to a garden.
When choosing ornamental grasses, know the expected mature size of the grass, both in height and width. Most grasses have tenacious root systems once established, which makes them quite drought-tolerant, but also difficult to transplant. Grasses can serve as a living fence, as an accent plant or grown in clusters for a bold statement. Grasses can also be grown in containers.
Most true grasses do best in full sun, with the exception of Japanese Forest Grass (Hakonechloa) which prefers the shade. It is a beautiful grass and comes in both a green or variegated form, but it is slow to establish, maturing at 18 inches tall by 2 feet wide. It is also not drought tolerant, which many other true grasses are.
Probably the most popular ornamental grass today is Pink Muhly grass (Muhlenbergia capillaris). Native to the eastern half of the US, this mid-sized grass forms a 3-foot by 3-foot clump of thin grass blades topped with showy purplish pink panicles of blooms starting in late summer to early fall, which persist usually until a killing frost.
Choices by size:
TALL
Pampas Grass (Cortaderia sp.) forms large clumps up to 10 feet tall and wide, with showy plumage in the fall.
Zebra Grass (Miscanthus sinensis ‘Zebrinus’ forms clumps 8 feet tall and 5 feet wide with striped foliage and fluffy white with a tinge of pink flower heads. Can become a bit aggressive over time.
Maiden Grass (Miscanthus sinensis ‘Gracillimus’) is slightly smaller than zebra grass with narrow foliage, and flowers later.
Switchgrass (Panicum sp) is native clumping prairie grass that can grow to 5 feet tall by 2 and a half feet wide. Slightly coarser texture with small, airy flower heads. Extremely drought-tolerant and long-lived.
MID-SIZED
Feather Reed Grass (Calamagrostis ‘Karl Foerster) has a more columnar growth habit, growing up to 4 feet tall but only 2 feet wide. Nice tan flower heads.
Little Bluestem (Andropogon scoparius), an upright grass with silvery blue stems grows to a lovely 2-to-3-foot-tall plant with fluffy, white flower heads in late summer through fall.
Perennial Fountain Grass (Pennisetum alopecuroides ‘Hamelin’) is an excellent upright ornamental grass, growing up to 3 feet tall with white flower heads that turn coppery in the fall.
Annual Fountain Grass grows to be around 3 feet tall and wide and comes in several varieties.
Annual Fountain Grass. (Pennisetum setaceum) Several annual varieties are available with dark purple coloring (Purple fountain grass or Burgundy Giant). Fireworks has pink-and-purple striped foliage. They can be overwintered if the plants are dug and moved indoors but will not overwinter outside. Great for containers, it grows 3 feet tall and wide.
SMALL
Blue Grama Grass (Bouteloua gracilis) or Blond Ambition is a native grass with interesting horizontal cream-colored flower heads.
Blue Fescue Grass (Festuca ovina ‘Glauca’) produces small mounds of silvery blue foliage.
Weeping Lovegrass (Eragrostis sp) features soft airy foliage with a weeping or cascading effect. Formerly used often for erosion control on steep banks.
GRASS-LIKE, but not true grasses:
Clumping Monkey Grass (Liriope muscarii) comes in green or variegated forms with lovely purple or white flowers. Can grow in sun or shade. Should be evergreen, but in a bad growing season would benefit from pruning prior to new growth to freshen it up.
Running Monkey Grass (Liriope spicata). Avoid this plant, as it can become highly invasive.
Mondo Grass (Ophiopogon sp) – is often referred to as dwarf monkey grass, this low growing thinner bladed plant can come in green or dark purple (black) foliaged forms. Does best in light to full shade.
Sweet Flag (Acorus gramineus) comes in several varieties of this grass-like groundcover for partial shade exist, with ‘Ogon’ being common with yellow foliage. Variegata has white and green leaves.
Sedges. (Carex morrowii) Green or variegated forms of this grass-like plant for shade and moist soils exis. Evergold is a yellow form, and Aureo variegata is a highly white-and-green variegated form.