Mondo Grass is a landscaping lifesaver for difficult-to-maintain areas or places you want a dense, natural-looking border.
The resiliency of Mondo Grass sets it apart. The plant tolerates a spectrum of weather and light conditions, which makes it easy to grow. But, this plant does require some specific attention to keep it healthy.
To help you learn how to grow Mondo Grass successfully, follow the tips in this guide. Inside, you’ll find details about Mondo Grass varieties, determine what conditions it needs to thrive, and steps to follow for planting.
By the end, you’ll be a Mondo Grass pro!
Mondo Grass Care Requirements
Mondo Grass is a perennial evergreen from the lily family. Once Mondo Grass establishes, it becomes one of the easiest plants to maintain.
To give your Mondo the best chance to flourish, set the stage by providing these following needs:
In most regions, the plant can survive in both full sun or full shade but does best in partial shade. The plant’s foliage will become lighter with full sun exposure and deep green in the shade.
Mondo Grass prospers in USDA zones 6 to 11 and is winter hardy. The plant will regrow after a freeze.
Mondo Grass thrives in humid environments. In dry regions, spritz the foliage with water often to increase humidity around the plant, or the leaves may turn brown.
For the hottest and driest zones, opt to plant your Mondo in the shade when possible since lack of moisture can make the grass look ragged.
Regularly water Mondo in regions where rainfall is scarce. An inch or so a week should suffice.
During the first season after planting, it’s critical to keep the soil moist. Still, after the first year, it becomes quite tolerant of drought conditions.
Slow down on watering during the fall and stop in the winter when growth stops.
A well-draining, nutrient-rich soil is best for Mondo Grass, but the plant can survive fairly well in just about any type of soil as long as there is sufficient moisture.
Planting Mondo Grass: Step by Step
Step 1: Location and Soil Prep
For new transplants, pick a location that provides filtered sunlight to avoid drying out the plant.
Amend the soil if it lacks good drainage or ample nutrients. Remove any weeds and till in some compost to the top six inches of soil.
Step 2: Dig Holes and Set Plants
Using a garden shovel, dig holes to set your transplants. The hole should be around four inches deep. You want to give the nodes and roots room, but the crown needs to stay above the soil surface.
Spacing depends on the coverage you desire and how patient you are to wait for areas to fill in. Plant the grass clump three or four inches apart for a full look. Planting six to eight inches apart gives each clump definition, but eventually, they will merge as they spread.
For transplants from your garden, split the cutting into sections with three or four nodes each per new plant.
Dwarf Mondo Grass looks best when you plant it about three inches apart.
Step 3: Backfill the Holes
Carefully backfill the holes with soil, taking care not to damage the root system or break off any stolons or nodes. Press the soil firmly down to hold the grass upright. Remember to keep the crown of the plant above the soil surface.
Step 4: Mulch
Protecting the soil surface from too much heat and keeping as much moisture in is critical when establishing Mondo Grass in a new location. Lay down a three-inch layer of mulch around the base of each plant, leaving space around the plant’s crown.
Step 5: Start a Watering Regime
During the first year of growing Mondo Grass, keeping the soil moist as much as possible will allow the root system to develop fully and keep the plants actively growing.
Watch the top inch or so of soil for dryness, then water as necessary depending on the region.
Mondo Grass Maintenance
Now that your Mondo Grass is in the ground and adequately watered, you should follow up with general maintenance tasks.
Using a diluted grass fertilizing product, fertilize the Mondo Grass twice a month from spring until the end of August for the first year after planting. Do not apply between September and early spring.
After that, only fertilize at the beginning of spring when new growth is evident, and maybe once again in summer if the grass seems stressed.
In place of commercial fertilizer, you can also add a half-inch of compost around the plants to boost nutrients and improve soil conditions.
Most gardeners propagate Mondo Grass by dividing large clumps to garner new plants instead of growing them from seed.
While plants do produce seeds, they need constant moisture to germinate, which can be challenging if you aren’t watching them every day.
To divide plants, gently dig out the clump or slice down into the cluster with a shovel. Once the grass is loose, pull apart small sections that include three or four nodes and replant in a new location.
Yes, you can mow or weed-eat Mondo Grass if the plants are too tall or look shabby.
The best time to trim them down is in the spring before the active growing stage begins. Never cut off too much of the plant, which can shock its development. Only cut off as much as you need to clean up any ragged or brown edges.
Dwarf species of Mondo Grass should never need a mow. However, if you want the tops to all look uniform, in the spring, run over them once with the mower. Make sure it’s set at its highest level to avoid causing any damage.
For such a carefree plant, Mondo Grass does have a few issues to watch out for. In most instances, the plant survives any pests or diseases and rebounds with fresh foliage in short order.
Snails and slugs
If your Mondo Grass appears to be dying, slugs and snails may be the culprit. These pests like to chew on the foliage, which will then yellow and wilt.
Look between the leaves of the grass for signs of snails or slugs. If you see the critters, put on a pair of gloves and remove as many as you can find.
Afterward, water the area and heavily sprinkle snail and slug bait control granules (iron phosphate is a crucial ingredient). Watch the issue fade away as the pests stop eating after they eat the granules.
Fungal infections and diseases
Spider mites are common to Mondo Grass and can cause yellow spots on the leaves. Thin webbing throughout the foliage is another sign spider mites have moved in.
Use a gentle spray on your hose to wash a spider mite infestation off the foliage. If that doesn’t work, use a quart-size sprayer full of water and four or five drops of liquid dish soap and spritz the foliage to kill the mites.
Plant disease is rare in Mondo Grass, but fungi can present a problem when the weather is rainy for long periods, and the foliage stays damp.
If you see dried, browning leaf tips that lead to yellow then falling leaves, a fungus called Pythium splendens is usually to blame. This fungus causes root rot and needs a fungicide treatment to eradicate the problem.
Use 1/3 ounce of a fungicide that includes the Gliocladium virens (strain GL-21) and mix it with a gallon of water. This amount should treat a ten-by-ten foot area. Wait for the Mondo Grass to dry, and apply the liquid evenly across the space using a garden sprayer when no rain is in the forecast for 24 hours.
Leaves turning yellow
When Mondo Grass leaves turn yellow, the most apparent reason will be super dry conditions, as this plant loves humidity.
Water with a super mist-like spray more often to amp up the moisture around the foliage. Remove the yellow leaves to improve the look of the plant and allow the fresh green foliage to fill in.
Before Mondo Grass can grow into a thick carpet, weeds can pop up in and around the plant.
Never use broadleaf weedkillers in your Mondo Grass, as it will kill the plant. The plant is a member of the lily family and not a true grass. The best course of action is to pull offending weeds by hand, which causes less damage to the plant.
If your mulch layer has deteriorated, reapply a new coat about three inches deep to deter new weed growth.
Mondo Grass Foliage
When planning your landscape design, it’s important to know the height, width, and coloration of Mondo Grass varieties. This will help you layout your planters and borders to create the most visual impact.
Here’s a list of what to expect:
- HEIGHT: Traditional Mondo Grass and Black Mondo Grass both grow to around 12 inches tall on average, but some will grow a bit higher or shorter. Dwarf Mondo Grass grows to around two to four inches tall.
- LEAVES: Mondo grass leaves of all varieties are long and thin, with a width of around 1/4 to 1/2-inch wide. Leaves are widest at the base and taper to nearly nothing at the tip.
- COLOR: Traditional Mondo Grass displays leaves that can be dark green all the way up to a light, nearly yellow-tone. This depends on how much direct sun the plant receives. Some varieties have a variegated stripe. Black mondo grass starts its young life with green leaves that mature over time to a black or deep burgundy tone. Dwarf Mondo Grass foliage is mostly a medium to dark green shade.
- FLOWERS: Traditional Mondo Grass produces a purple flower during the summer season. Black and Dwarf Mondo Grass will have a white flower. All the small flower clusters bloom off a long central stem.
- SIZE: At full maturity, Mondo and Black Mondo Grass form clumps about 12 to 16 inches in diameter. Dwarf Mondo grows into clumps about four to six inches wide.
Mondo Grass Varieties
Mondo Grass comes in three varieties, each with their own unique traits. Read on to find the perfect one to accent your garden.
Traditional Mondo Grass (Ophiopogon Japonicus)
This variety is the most common of the three types and is a hardy plant that can grow well in shady areas. The plant spreads over a foot wide. The dense green leaves fill in the soil and prevent weeds, which is a big help when planted in otherwise hard-to-grow areas of your yard.
Dwarf Mondo Grass (Ophiopogon Japonicus ‘Nanus’)
My favorite variety is the Dwarf Mondo Grass. Growing only two to four inches tall, the Dwarf is more resilient to weather extremes and easy to maintain. The plant spreads to fill in empty spaces and has a lush, deep color that highlights the flowers of your garden.
Black Mondo Grass (Ophiopogon Planiscapus ‘Nigrescensan’)
Black Mondo Grass is rare and stunning, yet is a slow grower and requires more water and full sun to partial shade. In warmer winters, it performs as an evergreen and keeps its color. Still, the dark tone of the foliage will only be apparent once the plant establishes itself.
Mondo Grass of any variety is a perfect landscaping addition for:
- Groundcover, especially in hard-to-maintain areas
- Filler for container gardens
- Borders along pathways or curbs
- Accents inside a rock garden
- Filler between paver stones
- An alternative to turf grass
Wherever your garden needs a visual boost, a patch of Mondo Grass will do the trick.
Keep in mind that Mondo grass has low levels of toxins that can cause gastrointestinal distress if chewed on or eaten. Keeps children and pets clear of Mondo Grass if they tend to chew on plant foliage.
Frequently Asked Questions
When is the best time of year to plant Mondo grass?
Plant mondo grass from spring through fall. The earlier in the spring, the better to help the plant establish long before the first frosts.
Is Mondo grass invasive?
While a moderately slow grower, Mondo Grass can be invasive. The plants can pop up in the soil several feet away from the primary grouping, which can be frustrating.
Mondo Grass originates from Southeast Asia and is not a native plant to the US, leading many to refer to it as an invasive species. The plant does spread much quicker in damp areas, so keep this in mind if you wish to contain it.
How much does Mondo grass cost?
A flat of 18 Mondo Grass plants averages between $35 to $50 depending on variety and your location. To cover a large area, you can purchase 54 pots of Mondo Grass for between $95 to $140.
If you are shipping the plants to your home, look for sellers that offer free shipping; otherwise, the final cost could increase dramatically.
How long does it take Mondo grass to spread?
Traditional and Black Mondo Grass is a slow grower that typically takes about two years to spread to full mature width.
Dwarf Mondo Grass takes even longer, clocking in at around three years for full growth.
Factors such as sunlight, water, fertilizer, and temperature affect the rate of growth. The plant also grows slower during its first year of transplant and spreads quicker in subsequent years.
If you want the immediate gratification of a thick carpet of Mondo Grass, go ahead and plant close together and plan to thin out the plants in a couple of years.
The bonus of slow spread is that the plant is much easier to corral when wayward plants begin growing where you don’t want them.