A bed of mondo grass flanks the front porch at Southwood Plantation in Tallahassee, FLorida. This is one of the dwarf cultivars with leaves only about 4 in long.
Mondo grass is an evergreen perennial that is actually a member of the lily family despite its appearance and common name. Depending on variety, the slender leaves grow from 2-12 in (5-30.5 cm) long. They are rigid and curve back toward the ground ("recurve") and resemble blades of turf grass. Leaves emerge in clumps from a network of rhizomes that grow just below the soil surface. With age the clumps will merge to form a soft dense carpet of foliage. In summer small light purple flowers are produced but are of little interest as they are hidden in the dense foliage as are the small blue-black berries that follow. Mondo grass resembles another "grassy" member of the lily family called liriope (Liriope muscari) which is also used for groundcover and borders. However, its flower stalks mondo grass are hidden within the mass of foliage, rather than above as in liriope. Blades are discernibly thinner than liriope, only about 1/8 in (0.3 cm) wide.
There are several dwarf cultivars of mondo grass available. With shorter leaves and more compact mounds and mats they are somewhat more formal than the casual species with its wind tossed foliage. 'Compactus' is the most compact with leaves that grow only to about 2 in (5 cm) long to form very low dense mats that I think resemble a fuzzy moss. 'Kyoto Dwarf' grows 2-4 in (5-10 cm). There is also a variegated cultivar that I have yet to encounter.
Mondo grass is native to shady forests and woodlands of Japan and Korea.
Likes fertile, well drained soil, but adapts well. May be fertilized during warm months, but seldom needs encouragement; The standard size spreads fast, and may need active measures to control invasiveness! The dwarf varieties tend to be much slower growing.
Light: Shade to partial sun Moisture: Water when soil is dry. Somewhat drought tolerant. Hardiness: USDA Zones 7 - 11 Propagation: Offsets or divisions. Very easy to propagate.
Mondo grass is a perfect low maintenance ground cover for shady areas. The dense foliage suppresses weeds and the long slender foliage is able to "consume" fallen leaves and other debris that falls into its embrace. The species, with 12 in (30.5 cm) leaves is shown in the photo, note that the dwarf selections don't hide fallen leaves as well but are still effective for edging out weeds.
Mondo grass is very useful as a ground cover for shady areas, and the dense mat of roots holds the ground exceedingly well where runoff is a problem. It is widely used as a border around beds, but can make a nuisance of itself by growing into the bed and out into the lawn as well where the ground is soft so use of a hard edging material is recommended. Good for edging walkways and defining beds; tall varieties may be used as foundation plantings. Mondo grass is quite pleasing to the senses as it ripples in the wind. Dwarf varieties are excellent as a groundcover around shady pools or garden statues, where height will not compete with the feature, and dark green will contrast better than a bright green grass, and will require no mowing. May also be used as an evergreen in planters, either alone or mixed with seasonal annuals for color.
A planting of black mondo grass (O. planiscapus 'Nigrescens')looks especially attractive in winter in Seattle's Mt. Washington park against the bright yellow stems of Cornus stolinfera 'Flaviramea'.
Mondo grass's rich dark green, finely textured evergreen foliage provides a handsome backdrop for more colorful plants. It is virtually pest and care free making it a great choice for low maintenance plantings. There are a couple other species of Ophiopogon that are also of interest to gardeners. O. planiscapus is similar in form but is available in varieties with almost black foliage. O. jaburan has wider leaves and is available in several varieties as well, the most popular being a variegated form.