Despite its name and appearance, mondo grass is actually a member of the lily family. Ophiopogon japonicus, as it is known to botanists, is a grass-like perennial native to tropical and mild temperate regions of East, Southeast, and South Asia.
It grows in clumps with arching, upright leaves and spreads by rhizomes. It produces spikes of pale lavender or white flowers in the summer, followed by clusters of blue fruits. Gardeners appreciate its slow growth habit, drought tolerance, and ability to look great with little care. In the United States, it is used extensively as a dependable, drought and shade-tolerant, ornamental groundcover.
Mondo Grass General Information
Ophiopogon is a slow-growing, evergreen perennial grown for its fine-textured, deep green foliage. It is hardy in USDA zones 7 through 11. It grows to about 12 inches tall with a clumping, slowly spreading habit.
The quarter-inch wide leaf blades have an upright, arching nature. In summer, it produces short spikes of white or lilac flowers, followed by bright blue berries in fall.
Mondo is easily confused with Liriope. They share a similar appearance and the common name “monkey grass,” but mondo is consistently smaller with narrower leaves. It also holds its summer flowers among the foliage before producing bright blue berries. The other monkey grass produces tall bloom spikes that rise above the leaves, followed by berries that are nearly black.
When used as turfgrass for a lawn, this groundcover tolerates light foot traffic, making it an excellent low-maintenance turf alternative for side yards and other seldom-traveled shady areas. Or, it can be used to protect exposed soil around tree roots and shaded slopes. It contrasts well with the medium and light green leaves on shrubs like azaleas, gardenias, and hydrangeas.
Several cultivars of Ophiopogon have been developed for more compact growth habits, or alternate foliage colors, such as dwarf, variegated, and black varieties. These are especially useful in rock gardens, container plantings, landscape borders, and many other settings. In mixed plantings, pair it with other perennials or annuals that prefer well-drained soil. Some good companion plants include astilbe, begonia, fern, hosta, heuchera, ivy, or sedum.
Black Mondo Grass
Dense, purple-black foliage provides a strong contrast for garden beds, borders, and container gardens. This variety produces deep lavender flowers in midsummer, followed in autumn by purple berries for an extended season of interest. Black Mondo works well in mass plantings, as border edging, or in mixed containers. It is hardy in zones 5 through 10. Plant in full sun for deep foliage color.
Dwarf Mondo Grass
At only half the size of the other varieties, Dwarf Mondo creates a lush, dense, dark green groundcover. It grows to 3 or 4 inches high, with a more pronounced, soft mounding habit, and spreads very slowly. Use it as a living border edge, or plant it among stepping stones. Hardy in zones 6 to 11. Plant in filtered sunlight.
Variegated Mondo Grass
Deep green leaves with silvery-white margins make Variegated Mondo pop in the landscape. It makes an excellent edging plant, bringing a strong color contrast to the other greens in the garden. Excellent for mass plantings and containers. Hardy in zones 6-9. Plant in full sun to partial shade.
Look for mondo grass in the groundcovers or perennials section at your local garden store. It is available in pots ranging from 4-inch to gallon size. For container plantings, choose a good general purpose outdoor potting mix. If they will be planted in the ground, remove existing vegetation and amend the soil by tilling in a three-inch layer of compost and soil conditioner, and starter fertilizer.
Remove the plant from its container and gently loosen the roots. Plant so that the upper soil surface of the plant is elevated above the surrounding grade by a half-inch. Space the plants 6 inches to one foot apart. Apply a three-inch layer of mulch, being careful not to cover the plants. Water deeply to soak the full depth of the root zone.
Mondo grass thrives in moist, well-drained soil. Throughout the first growing season after planting, it should be monitored and watered as needed to establish an extensive root system. In later years, it will only require irrigation during times of drought. In container plantings, water only when the soil is dry at a depth of two inches.
Constant overwatering leads to root rot and die off, so it’s best to err on the dry side. If you use an automated irrigation system, monitor the soil moisture weekly for the first few months after installation. Adjust the watering frequency and duration as needed to avoid problems.
This low maintenance landscape perennial grows best in soil with a pH of 5.0 to 6.5. It is a light feeder but benefits from a consistent feeding schedule. Fertilize when new growth emerges in early spring with a balanced, slow-release fertilizer or organic plant food.
Pruning And Division
No regular pruning is necessary. However, if the foliage looks bad at the end of winter, it can be cut back at that time, before the new growth emerges. Use a lawn mower with a sharp blade to make quick work of large mass plantings.
Mature plants can be divided in order to rejuvenate the bed or to provide plants for additional beds. Dig up a large clump of mondo grass. You will see where the stolons have spread to create new plants within the cluster. Use your hands or a sharp knife to break or cut away small plants off of the larger clump. Replant the “new” small plants wherever you need them.
Mondo grass has few pest or disease problems. Root rot due to pythium fungus becomes problematic where the soil remains too wet. When this happens, the foliage becomes discolored, new growth is slow or not existent, and the plant eventually dies. Avoid this issue by amending the soil for proper drainage before planting. If plants are lost to root rot, correct the drainage problem before replanting, or choose a more moisture tolerant plant.
Slugs and snails are attracted to the moisture and shelter beneath the grassy foliage, and they are happy to eat holes in the leaves. It may appear as if the plants are dying, but upon closer examination, the pests are visible near the base of the plant or within the foliage. In small plantings, you may be able to simply remove slugs and snails by hand. Treat heavy infestations with slug and snail bait.
For containers and landscape plantings, mondo grass is one of the most adaptable and dependable evergreen perennial accent plants. The fine texture and dark green color complement most other plants. Tolerance of different soil types, shade, drought, foot traffic, and other common plant stressors means that it grows well wherever the climate allows. With the least of care and maintenance, this plant simply thrives.