When homeowners plan landscapes or stroll through a garden center, they often gravitate to brightly colored flowers. And every garden needs some color, so that’s great. But flowering plants have seasons when they bloom, depending on the average temperatures in a low or high desert region. Ornamental grasses can fill the void left when other plants fade between seasons or just help balance a landscape. Here are five ways to incorporate ornamental grasses and a few favorites for Southwest gardens.
Introduce Movement with Ornamental Grasses
If there is one thing we have an abundance of in the Southwest, it is wind. The movement of greases in the wind is my favorite reason to have ornamental grasses. When everything fades in late fall and winter, many grasses really come into their own. The pretty seed heads sway in the wind and make me feel less depressed when it is too cold in the mountain areas to get outside.
Grasses to plant for movement: Silky or Mexican thread or feather grass (Nassella tenuissima) grows in zones 5 through 10 but is considered invasive in California; and Blue grama (Bouteloua gracilis), a native bunch grass that can take heat and cold. Also check out Side Oats grama and a new variety called Blonde Ambition. Purple fountain grass (Pennisetum setaceum ‘Purpureum’) is a gorgeous maroon-colored backdrop growing to about 3 feet high, and a perennial in zones 9 and 10.
Add Texture and Shape
Leafy flowering plants often have dark green, even glossy leaves. Many grasses have tall blades that break up the monotony. Add the “flowers” and seeds of ornamental grasses and you have a nice variety of textures. Use those textures in groupings or layers. Most grasses grow in a sort of V or cone shape with flowering at the ends, or top, or the plant.
Grasses for texture: Bear grass (Nolina varieties, especially N. texana), which loves sun (and heat through zone 11) and handles below-zero temperatures, gets a yucca-like shape with twisted ends. Another native is Wolftail (Lycurus phleoides, also called Texas Timothy) a warm-season native bunch grass that also feeds livestock throughout Arizona, New Mexico, Colorado, Texas and Oklahoma. Fiberoptic grass (Isolepis cernua) is an unusual compact grass that grows in zones 10 to 11 and can be an accent annual in containers in colder zones.
Form a Backdrop or Border With a Line of Ornamental Grasses
You might have a growing bed with lots of pretty but low flowering plants; maybe they all are the same height. A nice, tall native grass makes an excellent backdrop, especially against a wall or fence. You also can use bunch grasses to line a walkway, driveway or other area of your yard. Just plant anywhere from three or more of the same grass in a nice, neat row. You can get a uniform or symmetrical look without the formality of a hedge.
Grasses for backdrops and borders: Foerster’s Feather Reed Grass (Calamagrotis x acutiflora ‘Karl Koerster’), hardy in zones 4 through 9; Big Bluestem (Andropogon gerardii Vitman), a heat-loving native that can grow to nearly 8 feet tall in zones 4 through 9. Miscanthus varieties such as Zebra grass have pretty foliage and can grow as tall as 5 or 6 feet in zones 5 through 9. Pampas grasses love heat but can become huge; there are dwarf varieties such as Cortaderia selloana ‘Pumilla’
As I said, winter color can be drab in colder regions of the Southwest. Grasses add winter color because they tend to flower late in the season. In addition, the foliage of some grasses is red or varying shades of green to add accents in your landscape. Some, like pink muhly, have color in the seed fronds.
Grasses for color: Pink muhly (Muhlenbergia capillaris) with its stunning pink fronds, along with Mountain and Spike muhly, which have purplish heads. Indian ricegrass (Oryzopsis hymenoides) starts out dark green and then dries to a light straw color. Japanese blood grass (Imperata cylindrica ‘Rubra’) has red and green blades and grows in zone 5 to 9, and is a great desert-adapted grass, but check to see if it is invasive in your area. Other possible choices are some varieties of switchgrass (Panicum virgatum) and red sedge (though red sedge does best in wetter locations in your landscape).
Birds in particular love all native grasses. Small ones land on the seed fronds to gather seed, and other birds hop around on the ground to catch low-hanging fronds or fallen seeds. Other birds gather coarse blades from grasses such as miscanthus for nest material. Dried blades are especially easy for small birds to carry to nests. Some butterflies flock to native grasses in summer.
Grasses for wildlife: Blue and Sideoats grama, Big and Little bluestem; Muhly grass and Switchgrass
Cautions About Planting Some Ornamental Grasses
Most ornamental grasses need full sun, but afternoon shade might help them survive the hottest summer days. Some ornamental grasses, even native ones, can be invasive. Typically, the problem is a regional one and is less likely to occur in hot, dry areas of the Southwest than in cooler zones or in humid areas near the Atlantic coast. But that should not stop you from trying an ornamental grass you love; find a close alternative to any that behave like a weed locally. If a grass spreads by seed, it is easy to spot a new plant in your garden and remove or move it. Those that spread underground might be more difficult to control.