Liriope is a very popular ground cover in this area. It is one of the most inexpensive plants available at many nurseries. Also called lily turf, there are two main species and a number of cultivars of this Asian import. Liriope is evergreen, grows well under dry conditions, prefers shade but can handle sun, and looks a lot like grass. Both species of liriope grow only about one foot tall so they are perfect for borders or for surrounding trees and shrubs.
One kind of liriope grows in clumps (Liriope muscari) and has larger leaves and more colorful blossoms. The purple flowers, pictured at right, are produced on a single stem, followed by large, blue-black berries. Foliage of this plant comes in a number of colors, including solid green, yellow and green variegated, and white and green. My favorite is the yellow and green, with its large, gracefully arcing leaves and pretty blossoms. Although this species does not spread quickly, it does spread, and eventually can form a sizable patch.
The main feature of the other liriope species (Liriope spicata) is that it spreads aggressively. We obtained a number of pieces of this type over a decade ago and planted it under our live oak trees where it seemed that nothing else would grow. The liriope not only survived, but eventually formed a dense mat under the trees. It produces flowers that are small and almost white (photo at left), while spreading at a steady rate through the worst of soil and with practically no water. Now that we are improving the soil and discovering plants that we would like to grow in this garden, the liriope has to go. Over the years I planted various other flowers among the liriope plants, and many were choked out by the overpowering growth of the ground cover. It spreads by long underground rhizomes, producing small bulbs that grow bigger as the plant ages. Each bulb sprouts at least one and sometimes several clumps of thin, dark green glossy leaves. The roots have swollen growths for storing water, which look a lot like little potatoes.
Similar in appearance and use in landscaping, mondo grass (Ophiopogon japonicus) is sometimes confused with liriope. We have a couple varieties of mondo, or monkey, grass in our gardens, including the solid dark green kind, and a white and green variegated type. Although mondo grass grows in a fashion similar to the liriope, it spreads a little slower, produces unnoticeable blossoms, and has smaller, more wiry leaves only about 4 to 6 inches long. The variegated kind seems to need a little more water and has died off slightly during droughts. The dark green kind, however, is very drought tolerant and can handle sun and shade. Its small size and uniform foliage make it a desirable border plant.