Mondo grass is a shade-tolerant groundcover that is popular in gardens and yards throughout the southern US. Its lush green foliage helps provide definition and structure to the landscape, allowing the features of the garden to stand out.
Some folks are surprised to learn that mondo grass is not a true grass, but rather a member of the lily family. The plant grows in small clumps, with long blades that grow outward from the center. It is closely related to liriope muscari; however mondo grass blades are softer and floppier and tend to look more like turf grass.
Homeowners use mondo grass as a low-maintenance lawn alternative in areas of full or partial shade. Each clump sends out shoots that will gradually spread to produce a lush, dark-green lawn. Complete coverage typically takes from two to four years depending on the variety used and how closely the plants are spaced. This groundcover can withstand light to moderate foot traffic, but in areas of heavier traffic you will definitely want to consider using stepping stones.
Mondo is also frequently utilized as a garden border, between pavers, and in shady spots around the base of trees. It provides texture in rock gardens and can be used around features like garden ponds and statues.
Why Use Mondo Grass?
Since mondo is a lily and not a true grass it has several advantages over normal grass. First of all, mondo’s leaves will remain green throughout the winter months. When normal grass starts to turn brown as the temperatures get cool, mondo grass stays deep green all year round.
Secondly, mondo grass can thrive in shady areas where many other types of grasses struggle to grow. Many homeowners have areas of their yards that just don’t receive a lot of sunshine. Maybe there’s an abundance of trees or a tall structure that blocks out the sun. Mondo grass will do just fine in these shady spots.
Another benefit is that mondo is a relatively low-maintenance grass. It typically does not need to be mowed, although some folks like to set their mower to a high setting and trim it one a year in early spring. As a drought-tolerant plant, mondo grass does not require watering once it has established itself. It also typically requires no fertilizer.
Varieties of Mondo Grass
Regular mondo grass is known by its scientific name Ophiopogon japonicus. This plant grows to about 6-10 inches tall when mature. Small, white flowers appear in summer, but they are covered by the leaves and not very visible. Bright blue berries appear in the fall, which will attract birds.
A closely related variety is called dwarf mondo grass. Dwarf mondo is more closely cropped than regular mondo, growing only 2-4 inches in height. This variety has no blooms and prefers a well-drained soil and full shade. It tends to spread more slowly than regular mondo.
Super dwarf mondo grass, or kyoto dwarf, is the smallest mondo available. This plant has compact tufts with dark green blades and grows only about one inch tall. Super dwarf is often found in flower beds and bonsai arrangements.
Black mondo grass has a distinctive black foliage that provides a dramatic contrast with lighter colored plants. It is similar in size to regular mondo, with a height of 6-10 inches. It is used in rock gardens or as a border or groundcover.
The liriopes (liriope muscari and liriope spicata) are two related species that are often confused with mondo grass. These plants have thicker roots and are more cold-hardy than mondo. They are also larger plants that can grow up to 18 inches tall. Liriope muscari has a pronounced purple flower spike that blooms in mid to late summer. It is often used as a border or in a flower bed. Liriope spicata is the faster spreading of the two and is frequently used as erosion control on hillsides. The liriopes are sometimes referred to as monkey grass.
Where, When and How to Plant
Regular and dwarf mondo can grow in USDA Hardiness zones 6-10. These plants are frost hardy but will have trouble with temperatures that dip much below 0 degrees Fahrenheit. Black mondo tends to do slightly better in northern climates, as it is rated for zones 5-10.
In cooler climates, mondo grass should be planted in the spring or summer so it can establish itself before winter. In warmer areas, it may be planted year round.
Plant mondo grass in a well-draining location with full or partial shade. Till the soil and mix in 2 to 3 inches of compost. If planting bare root plants, prepare planting holes about 3 inches wide and 6 inches deep. Space plants 4 to 12 inches apart. If using dwarf or super dwarf varieties, use a 2 to 4-inch spacing. Spread the roots and work the soil in around them, making sure all the roots are well covered. Gently tamp the soil around them to remove air pockets. Mulch around young plants with straw or wood mulch to retain moisture and keep weeds at bay.
Water the mondo and keep the soil moist for the first 3 to 6 months to allow the plants to establish roots. One the roots are established you can cut back to watering only when the soil is dry.
Mondo grass is quite easy to care for. Light fertilizer applications in the spring will help maintain color and increase growth rate, but they are not required. An annual mowing in early spring can stimulate growth, but take care to set your mower to a high setting because the plants can be damaged if cut back too much. Rake the grass as needed to remove dead leaves.
Once the mondo has spread to fill in an area the plants should be able to choke out most weeds. Weeds can be a problem in the early stages when the plants are still filling in. Hand pull weeds or spot treat them with a post-emergent herbicide. Make sure the herbicide is labeled for mondo grass (Ophiopogon japonicus), as some brands may not be appropriate for this plant.