Terrific as edging along a sidewalk, the front of a flower bed or massed as a ground cover under a shady tree, liriope proves to be a durable, low-maintenance perennial. Sometimes called lilyturf, border grass or monkey grass, it is not a grass at all but a member of the lily family. The tufted to spreading clusters of thin leaves look attractive, but in late summer to early autumn lavender to white flowers poke upwards, adding to the textural interest. Grow liriope successfully in U.S. Department of Agriculture hardiness zones 6 through 10.
Common species of liriope available at nurseries and grown in home gardens include Liriope muscari, the big blue lilyturf and spreading lilyturf, Liriope spicata. Both prosper in locations where soil is crumbly and moist but drains well and is not alkaline in pH. They grow nicely in full-sun to nearly full-shade light exposures, allowing them to grow as an edging to the lawn or under the wide-reaching branches of deciduous shade trees. In regions where plants are marginally hardy, consider planting liriope, sheltered from hot or cold drying winds.
Soil quality involves moisture retention and fertility issues. While a loam rich in organic matter is an ideal soil for growing liriope, both sand and clay soils can be improved simply by incorporating lots of organic matter. Compost and well-cured manures used as a mulch or top dressing around liriope plants improves soil quality, fertility and water drainage. Application of man-made fertilizers isn't necessary if the soil is continually layered with organic materials to naturally break down and sustain plants. An occasional scattering of slow-release granular fertilizer such as 10-10-10 in spring certainly does not hinder lush growth.
Liriope falters in both excessively dry and waterlogged, soggy soils. Once the root systems of these perennials establish, liriope is drought tolerant. In the growing season, plants need 1 inch of rainfall or irrigation weekly, less during the cool weather of the winter dormancy. Overly humid conditions and over-watering promotes fungal rot of roots and leaf bases, and favors a habitat for hungry slugs and snails. Plants in lots of sun may need more watering than those in shady situations, but be aware that liriope grown under trees may need more water since tree roots also compete for the same resources.
After three to five years of growth, clumps of liriope may become massive, spread into undesirable areas or lose vigor in the center of the leaf tufts. Digging up plants and dividing the mass of roots and replanting them is best conducted in spring before new leafy growth gets underway. Slice root balls with a garden shovel into smaller-sized clumps that are easy to handle, then immediately replant them, taking care to plant them at the same depth as before. Match the top of the root ball with that of the planting hole so you don't plant liriope too deeply, which will lead to fungal rot and future death.
After a severe drought or brutally cold winter, the evergreen foliage of liriope often looks tattered and unkempt. In early to mid-spring, give liriope plants a "haircut" by shearing off all foliage with pruners or a weed-cutter to a height of 2 inches. Soon the new spring growth emerges and rejuvenates the clumps with exceptionally good-looking, vibrantly colored leaves. Don't do trimming past midsummer or in the middle of a severe drought. Gardeners sometimes choose to trim their liriope plants every year each spring to create the most beautiful foliage plants.
Spreading liriope, Liriope spicata, can have their sprawling roots sliced anytime of year to pull out young plants. Place the garden shovel blade near the clump base and slice the roots to sever the spreading young plants from the mother. Pull out the little plants and compost them and smooth and tamp the soil back around the mother plant to keep it looking tidy. Occasionally little seedlings of liriope may pop up around the garden, thanks to the black fruits produced after the flowers.