Black Mondo Grass: A Dark, Lovely Ground Cover
Dark and distinctive, black mondo grass is a fascinating ground cover. Learn how to use it in your garden with our growing guide!
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Do you have a bit of a spooky streak? Love plants that look like they should grow outside that haunted house on the hill? Black mondo grass is the ideal low-maintenance, creepy ground cover. But it also looks amazing even outside of a goth’s garden!
Also known as Ophiopogon planiscapus, black mondo grass is a drought-tolerant plant that isn’t technically a grass. It’s part of the same plant family as asparagus, in fact. Hovering within eight inches of the ground, black mondo grass can form a darker contrast to a bright floral display.
For dramatic flair, black mondo grass can’t be beat. It’s not just a plant for Halloween anymore. This ghoulish garden-dweller can also be a glorious bedding plant. And it produces flowers, too!
So let’s explore this dark and mysterious black mondo grass in depth. We’ll eliminate its eerie image and show you how best to bring this stunner to light in your yard. All this so you can plant black mondo grass at home!
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Overview
| Scientific Name: | Ophiopogon planiscapus nigrescens |
| Common Name(s): | Black mondo grass, lilyturf, monkey grass, black mondo |
| Family: | Asparagaceae |
| Height & Spread: | 8-12″ tall, 12-24″ wide |
| Sun: | Full to partial sun depending on placement |
| Soil: | Slightly acidic, humus-rich, well-draining |
| Water: | Evenly moist soil, do not overwater |
| Pests & Diseases: | Snails & slugs, root rot (pythium especially) |
All About Black Mondo Grass
In all seriousness, black mondo grass is nowhere near as dark and foreboding as I suggested earlier. Low-maintenance, it looks beautiful as a border edging or dappled through rock gardens. Known botanically as Ophiopogon planiscapus nigrescens, it has common names that include Black mondo grass, lilyturf, and monkey grass.
The long, slender and strap-like leaves of black mondo grass can range from green to purplish-black. The warmer the weather, the darker their coloring becomes. That deep coloration can provide a dramatic counterpoint to brighter blossoms.
Not all forms of mondo plant are black! There are cultivars that are much lighter in color. While they also darken in the sun’s warmth, their edges can stay off-white. The centers of the leaves remain a dark green hue. Lighter plants are often called lilyturf, a name often used for Liriope species as well.
Forming tight, matted clumps in its bed, the black mondo grass perennial grows in zones 6-10. It provides year-round color in those zones, but its active growing season occurs in spring and summer. Called monkey grass in the southern US, this plant also produces flowers on a long, slender raceme in fall.
The native origins of black mondo grass are in Japan, but it’s traveled around the globe. Because of its unique coloration, it’s become a dramatic contrast plant for landscaping.
Types Of Mondo Grass
Ophiopogon is a large genus. There are quite a few related plants to mondo grass. While we’re focusing on Ophiopogon planiscapus today, don’t rule out the black mondo grass cousins! I’ll mention two with similar growth habits and tendencies to mondo grass.
But let’s talk lilyturf first. There are a few popular cultivars to zero in on.
Ophiopogon planiscapus ‘Nigrescens’
This is the deepest and the darkest variety, the one which gave mondo grass its “black” name. Reported to have a sweet fragrance, it blooms with lavender to purple bell-shaped flowers. In time, these flowers produce an inedible berry that holds its seeds.
The long leaves of this black mondo grass begin as dark green but deepen in the heat to become so dark they turn charcoal-colored. Slightly reflective, they can have a greyish cast to them in certain lighting. These can survive in USDA zones 5-10 but do especially well in zones 7-9.
Ophiopogon planiscapus ‘Little Tabby’ or ‘Silver Ribbon’
A pair of popular cultivars, Little Tabby and Silver Ribbon, are both similar in color. These are more commonly called lilyturf or monkey grass than mondo grass. Silvery-white edges fade into a vivid, dark green leaf.
The flowers for these are white but also morph into a deep purple-colored inedible berry as they fade. These are sometimes confused with Ophiopogon intermedius, called Aztec grass. But Aztec grass grows to 12-24″ in height, where these stay closer to the ground.
Other Related Species
Ophiopogon japonicas, ‘Mondograss’ or ‘Fountain Plant’
While it shares the common name of mondograss, O. japonica has wider leaves and larger flowers. Many dwarf cultivars of this have been developed. Popular varieties include “Albus,” “Kyoto Dwarf,” and “Silver Mist.”
Only reaching a height of 2-3″ tall, it makes a beautiful miniature form and is often used in fairy gardens. This species tends to stay deep green in coloration. Its blooms are white to lavender.
Ophiopogon umbraticola or chingii
Even more slender-leaved than its kin, O. umbraticola has the synonym of O. chingii. Originating in China, it grows 4-6″ in height and produces white flowers. It tends to be less erect than planiscapus, looking a bit like a more unruly grass.
Also, unlike its relatives, this one does not spread through rhizome-like roots. It stays put quite well. For a pop of vivid green color, this plant works well. It will not spread to form a ground cover, so to use it that way you will need to plant densely.
Ophiopogon intermedius, ‘Aztec Grass’
Aztec grass tends to be a larger plant, suitable as a decorative bedding plant. Its leaves are striped pale green and white, and it doesn’t reach the darker colors that its cousins do. Heights of 18-24″ are not uncommon in larger specimens.
I like this white-flowering plant as a border plant. It’s quite popular in the south to southeastern US. Alas, it doesn’t hold up to the winter cold in the northern portions of the country. It prefers USDA zones 7-10 for best growth.
Be forewarned: Aztec grass spreads rampantly and can become invasive if it likes your climate.
Care
But how does one practice proper black mondo grass care? How drought-tolerant is it, really, and what’s the best soil blend? Let’s talk about that!
Light & Temperature
Full sun to partial shade is what’s recommended for black mondo grass, but it should be a “cool full sun” condition. If you’re in a hot, desert-like climate, afternoon shade is preferable. Too much full sun or direct sunlight in extreme heat can damage the tender leaves.
Black mondo grass is considered “cold-hardy”, but that should actually mean “frost-tolerant”. If you get hard freezes, your plant will suffer. The rare light frost shouldn’t do more than cosmetic damage.
Water & Humidity
While Ophiopogons have relatively mild water requirements, they still need moisture. With these, maintaining a consistently-damp soil is going to help keep them healthy. Consistent watering also improves flowering capability. However, they do not like overly wet conditions.
During the first year after planting, water black mondo grass a bit more regularly. After it’s established, it can tolerate the occasional dry period. But it does still prefer even moisture levels.
A mulch can help maintain the moisture of the soil around black mondo grass. Those in direct sunlight will thank you. Opt for something which sets off the look of the grass-like leaves well, like a contrasting wood chip.
Black mondo grass is tolerant of humidity as long as there’s good airflow around its location. If it’s boxed in and the air is hot and sticky, it may wilt a bit.
Soil
Humus-rich, slightly-acidic well-draining soil is best for your black mondo grass. Aim for a pH range between 5.5 and 6.5 for best growth. Avoid clay-like soils when possible, as these are too hard for the roots to penetrate easily.
Excess water needs to drain away to prevent root damage. Avoid muddy conditions, especially in hot climates!
Fertilizer
Fertilizing black mondo grass with a balanced fertilizer should be rare. A spring application of compost around the plant’s base should be more than enough to feed it and support the plant’s health.
Propagation
While black mondo grass will spread, its spread is very slow. It’s much easier to divide off new plants in the spring.
Remove a large clump of black mondo grass from the soil, being careful to not harm its fibrous root system. Dust off excess soil. Using your hands, separate off smaller clumps, each with its own roots and leaves.
Once separated, you can plant black mondo grass at 4″ intervals to provide a good cover. Carry out mass planting of large quantities of plugs and you’ll have an entire garden of the stuff.
You can grow black mondo grass from seed contained within its purple berries, but it is time-intensive. Black mondo seed has a low germination rate. It’s also slow to germinate and can take anywhere from 30-150 days. Since it’s a slow-growing plant, preparing enough starts for a ground cover takes a while!
Pruning
Some sources have suggested mowing your black mondo grass. Please don’t do that. It can take months to years to recover.
This plant seldom, if ever, needs pruning. Instead, remove dead or disfigured leaves as necessary. Pruning is wholly cosmetic.
Problems
As long as it’s given the right conditions, your black mondo grass plants will thrive. But what if they’re not performing right? Now that we’ve talked about black mondo grass care let’s troubleshoot.
Growing Problems And Diseases
The biggest problem you’re likely to face – especially in mass planting areas – is pythium root rots. This fungal rot can develop when the soil is too moist, causing yellowing and browning of the plant’s leaves. If not treated, it can lead to black mondo grass plant death.
Treatment of root rot should begin by reducing your watering regimen. Apply a biological fungicide like Serenade Garden Disease Control per the manufacturer’s recommendation. Bacillus subtilis, the active ingredient in Serenade, helps control and prevent pythium.
Underwatering can cause black mondo grass plant wilting. Plants in direct sunlight are more susceptible. If the soil is dry more than an inch below the surface, it’s time to water. Consider adding mulch to slow the evaporation of soil moisture, especially in zones with extreme heat.
Avoid excessive pruning, as the plant grows quite slowly. Too much pruning will make it look less appealing.
Pests
Most pests seem to ignore black mondo grass!
But there are two that don’t, both related: snails and slugs. These can chew holes in leaves or gnaw the leaves right off your gorgeous black mondo grass. An application of an organic snail bait like Garden Safe Slug & Snail Bait is a good choice. This bait lures them away from plants and kills them off.
Frequently Asked Questions
Q. What is the difference between Lily Turf and black mondo grass?
A. Part of the confusion is due to the common names. Black lilyturf is a common name for black mondo grass. Lilyturf also refers to the lighter shades of mondo. And it’s also the common name for some Liriope species.
For this plant, it’s easiest to go by botanical name to be sure you’re getting what you want!
Q. When is the best time to propagate mondo grass?
A: I like to divide my black mondo grass plants in the early spring before they resume active growth.
Seeds can be sown at any time of year as long as the conditions are right, but should be started indoors. Do not plant out seedling plants until all danger of frost has passed in the spring.
Q. How often should I fertilize mondo grass?
A: Honestly? Don’t. Just add a half-inch to an inch of compost around the base of the black mondo grass plants in the spring. That’s all the nutrition they need.
Once dark and foreboding in aura, by now you know better. Black mondo grass, like its lighter cousins, doesn’t have to be a ghoulish delight. Use it as a foil for your bright blooms. Pair them in mixed containers some with gaily-colored sweet potato vine for an astounding display. And appreciate the rich, dark color for what it is: a distinctive and different ground cover plant worthy of growing.
