With their arching, grass-like leaves and delicate spikes of flowers, lily turf (Liriope sp.) makes an attractive ground cover. Two popular choices of this plant are creeping lily turf (Liriope spicata) and blue lily turf (Liriope muscari). Although they have some similar features, knowing the differences between these plants will help you make the best choice for your garden.
Both blue lily turf and creeping lily turf grow in moist, well-drained soils and can be grown in full sun to partially shaded areas of the garden. The difference between these two is their cold tolerance. Blue lily turf is hardy to U.S. Department of Agriculture hardiness zones 5 through 10, but creeping lily turf is slightly more cold tolerant and can survive in USDA hardiness zones 4 through 10.
Blue lily turf and creeping lily turf both bear dark green, blade-like foliage. Blue lily turf forms 12- to 16-inch tall mounds that spread 8- to 12-inches across. The creeping variety stays about 8- to 12-inches tall but has a spread of 12-to-16 inches. The blue-purple flower spikes on blue lily turf are more showy and prominent than the white-to-lavender flowers of creeping lily turf. In areas without freezing winters, the plants are evergreen. The leaves of both species turn yellow and then brown during long freezes.
Because creeping lily turf spreads by fast-growing underground stems, the plant has a tendency to become invasive and is classified as an invasive species in some states. The blue variety spreads by adding growth to the clump, not by underground stems, giving this species less invasive potential. Both species compete with the roots of other plants. Although neither species has trouble with disease or insects, slugs and snails can be a problem.
Blue lily turf offers more varieties beyond the most common one. Creeping lily turf has only one commonly found option to the basic type, and that is "Silver Dragon." This variety has leaves with silvery stripes and spreads less quickly than the species standard. With blue lily turf you can choose from varieties such as "Gold Band," with its green and gold striped leaves; "Monroe's White," which has large spikes of white flowers; "Big Blue," which can handle dry conditions; and "Royal Purple," which has showy, deep purple flowers.