When I google ornamental grasses, I get a confusing variety of grasses of different heights and colors. How are these grasses used in landscaping? I’ve organized these grasses into 3 categories with each category having particular use in landscaping. This simplifies the whole process of choosing ornamental grasses.
Short Ornamental Grasses
Short ornamental grasses, 1-2′ tall, are used for edging or for a ground cover. For example, you can edge foundation plants, flower beds, or walkways with Liriope or Mondo. If you have a shady area where ordinary grass won’t grow, then a variety of carex could be used as a ground cover. This is a list of the most commonly used short ornamental grasses.
Acorus gramineus Ogon is evergreen and grows in zones 5-11. It has buttery yellow variegated foliage and can be used as an accent. Growing 12″ tall in sun or part shade, it spreads by underground rhizomes and likes wet areas.
Carex morrowii Ice Dance is hardy in zones 3-9 and is evergreen in zones 8-9. It has dark green leaves with a white edge and grows 1′ x1′. It also likes wet soil in part sun or shade.
Carex flacca Blue Zinger has bright blue foliage and is evergreen in warm climates. It is hardy in zones 5-9 in part sun or shade and grows 1′ x 2′.
Festuca glauca Elijah Blue is hardy in zones 4-8 and grows 10″ x 1′. This variety is evergreen and most tolerant of hot and humid summers. The bright blue foliage is striking.
Eragrostis spectabilis, often called purple love grass grows in zones 5-9 and has rose-purple panicles. It can reach 2′ x 3′ and spreads by rhizomes in sun and is tolerant of dry and infertile soil. It can be used where shrubs struggle to survive.
Hakonechloa macro or Japanese forest grass is hardy in zones 5-9 and has bright green blades that turn to coppery orange shades in fall. It does best in a shady moist area and can grow 2′ x 2′.
Juncus inflexus Blue Arrows is a great vertical accent with evergreen blue leaves that stay blue even in winter. It is hardy in zones 4-9 and grows 2′ x 18″. This grass is also used a lot in pots with annuals and near water ponds.
Liripe muscari Big Blue is evergreen and grows in sun or shade in zones 5-10. It blooms in late summer with purple spikes and grows to 1′ x 1′.
Liriope muscari Okina is a new variety where the top 2/3 of each blade is pure white while the lower 1/3 of each blade is green. It can be used as a ground cover in shady areas.
Ophiogon japonicus or mondo grass is evergreen and grows in zones 7-10. It forms a weed-proof mat 12″ x 15″ and makes a great ground cover or edger in sun or shade.
Sisyrinchium angustifolium Lucern is called blue-eyed grass and grows in zones 5-9 in sun or part shade. It has purple blooms in spring and summer and grows 10″ x 12″.
Medium Tall Ornamental Grasses
Medium-sized ornamental grasses grow 2′-4′ and are used as accents or as a shrub replacement in areas where shrubs won’t grow well such as wet or dry areas.
Helicotrichon sempervirens or blue oat grass is semi-evergreen and hardy in zones 4-8. It has straw-colored panicles in summer and grows 2-5′ tall and 2′ wide in sun or part shade and prefers dry soils.
Leymus arenarius or Elymus arenarius is called blue lyme grass and is and is an aggressive spreader used for erosion control or contained in planters. It is hardy in zones 4-10 and can grow 3′ x 3′ in the sun and has steel blue blades that turn yellow or rose in fall. It is evergreen in warm climates.
Muhlenbergia capillaris is often called cotton candy grass because in fall clouds of pink flower panicles are produced on a 3′ x 3′ arching green grass. This grass is very stunning in large drifts but also works as an accent. It is hardy in zones 6-10 and tolerates dry infertile soil in full sun.
Miscanthus sinensis Little Kitten has narrow arching green leaves that turn golden brown in fall. Its creamy flower plumes also turn golden in fall and provide winter interest. It is hardy in zones 5-9 and can grow 3′ x 2′ in full sun and moist soil.
Panicum virgatum Squaw is a vertical green grass that turns burgundy in fall. It has pink panicles and can tolerate clay, sand, and drought in zones 4-9. It grows to almost 4′ tall and 3′ wide in full sun.
Pennisetum oriental Karley Rose has dark green foliage that turns golden tan in fall and has rose-purple bottlebrush-like flowers from early summer to fall. It is hardy in zones 5-9 and grows 3′ x 3′ in the sun,
Pennisetum setaceum Rubrum is called purple fountain grass and is only hardy in zones 9-11. It is a fast-growing annual in most climates, growing 4′ x 4′ in full sun, The burgundy foliage with arching crimson plumes makes an exotic specimen.
Schizachyrium scoparium The Blues is a new variety that has blue foliage with red stems and in fall, the foliage turns to orange-pink and red colors. The grass grows upright to 3′ x 2′ in zones 4-9 in dry soil and full sun.
Tall Ornamental Grasses
Tall ornamental grasses are used as accents, hedges, and screens. They also provide shelter for birds and wildlife in winter.
Cortaderia selloana Pumila is a very large, 6′ x 4′, evergreen arching grass, with huge silky white plumes, This variety of Pampas grass will grow in zones 6-10, while most varieties only grow in zones 8-10. It tolerates drought and almost any soil condition and is mainly used as a specimen. However, pampas grass also makes a nice border hedge and grows fast in sun.
Calamagrostis x acutiflora Karl Foerster grows vertically and has feathery pink-purple flowers that turn golden in fall. It grows 5′ x 2′ in the sun or part shade and is often used to hide garbage cans or air conditioner units. It can also grow in clay or wet soils.
Chasmanthium latifolium or northern sea oats grows in zones 5-10 and in just about any conditions, including sun or dry shade. It can reach 5′ in sun and turns light brown in winter.
Miscanthus sinensis Morning Light is a vase-shaped grass growing to 6′ x 4′ in zones 5-9, Its green foliage sways gracefully in breezes and red plumes in fall turn white in winter. It needs full sun and can be used as an accent or hedge but also as a screen to hide unpleasant views.
Miscanthus sinensis Zebrinus is another variety that has variegated foliage. This green grass has yellow stripes that turn golden in fall and tan in winter. Its red plumes in fall turn white in winter and it can grow 8′ x 6′ in zones 5-9 and needs sun.
Panicum virgatum Heavy Metal grows vertically to 5′ x2′ and has metallic-blue foliage that turns yellow in Fall. It tolerates wet or dry conditions and full sun or half shade. This grass makes an excellent specimen or hedge.
Conclusion
There are a lot more varieties of Pennisetum, Miscanthus, and Panicum that I have not listed, and more varieties coming out almost yearly. They all provide the same function such as screening, hedging, and providing accents in the landscape. Don’t forget to add some colorful grasses to your landscape!