Plants of the Week: Perennial Ryegrass and Tall Fescue
There are an amazing variety of beautiful grasses growing on the High Line. Little bluestem is an unexpected, cooling blue-green in midsummer. The flowers of purple love grass explode into airy fireworks, and then break away and float down the High Line like tumbleweeds in late summer. Switchgrass – with its autumnal burgundies and mauves – gives depth of color and texture to the late fall and winter landscape. These are just a few examples of the dazzling range of colors, textures, and forms that the grasses lend to the park’s landscape. However, there are two species of grass on the High Line in particular that hardly ever get acknowledged. Lolium perenne, perennial ryegrass, and Festuca arundinacea, tall fescue, are the hardworking turf grasses that make up the High Line’s 23rd Street Lawn, and this week we give them their due.
Turf grasses are plants that are specially bred to optimize each species’s natural qualities. Most lawns contain a mix of these species in order to get the benefits of each one. For instance, the Lawn on the High Line is made up of a blend of approximately 20% perennial ryegrass plants and 80% tall fescue plants. Each of these species serves its own purpose in helping to keep the Lawn green and lush in the particular conditions of the park’s environment.
Both species are cool season grasses, meaning their periods of growth are spurred by the cooler weather of New York’s spring and autumn, and they both tolerate the partial shade thrown by the buildings adjacent to the High Line. Lolium perenne, perennial ryegrass, is quicker to germinate and grows rapidly, so it out-competes weeds in the Lawn. Because it rejuvenates so quickly, it’s more wear-resistant than many turf plants and can better stand up to the thousands of visitors who use the Lawn on the High Line every day. Lolium perenne is also known for its deep, dark emerald-green color.
Festuca arundinacea, tall fescue, is used in the High Line Lawn partly for its ability to stand up to warm summer temperatures in the city and partly for its spreading growth habit, which helps to fill in bare patches quickly. Primarily, though, tall fescue is useful and interesting, because of its disease and pest resistance, which is due to a symbiotic relationship with fungi growing between its cells. This is a naturally occurring relationship – often enhanced by breeders – in which the fungi draw nutrients from the plant and in return create alkaloids with insecticidal properties. These fungi can also act as barriers to disease-causing fungi that might infect the plant.
Despite the turf-worthy qualities of the plants that make up the High Line’s Lawn, it still takes a significant amount of care to keep the grass green. The Lawn is closed Mondays and Tuesdays throughout the season for much need restoration after the heavy traffic of weekends, and also following heavy rainfalls. Next time you’re enjoying the Lawn, think of the thousands of individual Lolium perenne and Festuca arundinacea that come together to make this space so beautiful.