Ornamental grasses are a part of the landscape that is often taken for granted. Usually, when someone is considering plants to add to their garden, they want something with showy flowers or other standout features like nice fall color. In fact, grasses can be showy, have an excellent variety of colors in the fall and much more. They look great during the growing season and retain interest through the winter, when most plants are fast asleep.
The best part is that many of the ornamental grasses are native- you can go out into a meadow and see the same ones used in the landscape.
Before I started working for The Parklands as a gardener, I knew only the basics about ornamental grasses and had little appreciation for the value they can add to a landscape. The more I worked with them, I realized how impressive they can be. Grasses add diversity in color and texture to garden beds, and exist in sizes ranging from about a foot tall to a towering fifteen feet! They can be used as screens, in foundation plantings, in perennial borders, in masses or in small groups.
One of the most important things to know when choosing a grass is whether it is a cool season or warm season grass.
Cool season grasses emerge early in spring and have an immediate impact in the garden, but they will slow their growth substantially and most likely turn brown during the hotter months without watering. Once temperatures cool down in the fall, they will resume growing. Examples of cool season grasses include Tufted Hair Grass (Deschampsia) and Bottlebrush (Elymus). Warm season grasses start growing near the end of spring and beginning of summer, when temperatures have warmed and stabilized. They grow until temperatures drop in the fall, when they begin to go dormant. This is the time of year that I enjoy ornamental grasses the most- a lot of them take on some brilliant colors and have fantastic seed heads. Examples of warm season grasses include Switchgrass (Panicum), Little Bluestem (Schizachyrium) and Prairie Dropseed (Sporobolus).
In order to prevent bare spots in the garden, it can be wise to plant a combination of both types of grasses so that one is growing while the other is dormant.
Grasses can be further categorized as spreading or clump-forming. Grasses that spread by rhizomes tend to be aggressive and can become invasive in the landscape. Clump-forming grasses tend to do better in perennial beds because you can keep them in-bounds. Nearly all ornamental grasses used in the landscape are perennial, so they will return year after year. It has become too common to cut back perennials or grasses in the fall just for the sake of having something to cut back, so wait until early spring for cool season grasses and late spring for warm season grasses.
To keep your grasses looking their best, a good rule of thumb is to divide them every third year while they are actively growing, but not while they are flowering. For warm season grasses this means anytime from late Spring when they begin to grow until mid-summer. For cool season grasses, the best time is spring. Generally, ornamental grasses do not require any fertilizer and some will even thrive in poor soils.
Another positive aspect is that neither deer nor insects seem to feed on ornamental grasses.
There are many other benefits of using these grasses. They have incredible value for wildlife. The seeds are a valuable food source for birds during the months when food is scarce or snow is covering the ground. Birds, insects and small mammals will use the grass as shelter and protection from predators, and larger animals like deer will even use it to hide their fawns. Some grasses, such as Switchgrass and a sterile, noninvasive hybrid of Miscanthus, are being studied for potential use as biofuels in the form of ethanol and butanol. Because of the structure of their roots, ornamental grasses are also good choices for erosion control plantings on sloped areas or to retain topsoil in more flat areas.
If you would like to see examples of any of these grasses, there are many places in the park to explore: The Garden Gateway, the hillside planting seen as you enter Beckley Creek Park from Shelbyville Road, includes masses of Switchgrass, Little Bluestem and Bottlebrush. You can find Tufted Hair Grass, Indian Grass (Sorghastrum) and Muhly Grass (Muhlenbergia) in the Creekside Center. Other grasses that can be found in the park include Northern Sea Oats (Chasmanthium) and Prairie Dropseed, located in the Humana Grand Allee.
If you have any questions about ornamental grasses, the park or plants in general, I am happy to answer e-mails sent to firstname.lastname@example.org.
Matt Jenne was born and raised in Louisville, KY. He attended Eastern Kentucky University and graduated with a Bachelors Degree in Horticulture in 2012. While he was in school, he worked for Louisville Metro Parks as a member of the Landscape Division. Matt started as a Park Attendant for the Parklands in early 2013 and was promoted to Zone Gardener shortly afterwards. He currently manages the plantings in the Humana Grand Allee, and also runs his own landscape business on the side. In his free time, Matt enjoys hiking, camping and gardening.
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