Black Mondo Grass: A Dark, Lovely Ground Cover

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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 creepy ground cover. But it also looks amazing even outside of a goth’s garden!

Also known as Ophiopogon planiscapus, this drought-tolerant plant isn’t technically a grass. It’s part of the same plant family as asparagus, in fact. Hovering within eight inches of the ground, it can form a darker contrast to a bright floral display.

For dramatic flair, it 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.

Good Products For Growing Black Mondo Plant:

Overview

Black mondo grass
Black mondo grass is actually an incredibly deep purple color. Source: Julia Manzerova
Scientific Name:Ophiopogon planiscapus
Common Name(s):Black mondo grass, lilyturf, monkey grass
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, 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.

Its long, slender and strap-like leaves 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 which are much lighter in color. While they too 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, this grasslike perennial grows in zones 6-10. It provides year-round color in those zones. Called monkey grass in the southern US, this plant also produces flowers on a long, slender raceme in fall.

Its native origins 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’s quite a few related plants to mondo grass. While we’re focusing on Ophiopogon planiscapus today, don’t rule out its cousins! I’ll mention two which have similar growth habits and tendencies to mondo grass.

But let’s talk lilyturf first. There’s a few popular cultivars to zero in on.

Ophiopogon planiscapus ‘Nigrescens’

Black mondo Nigrescens
The Nigrescens variety is a popular black mondo type. Source: BlueBec

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 which holds its seeds.

The long leaves 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’

Ophiopogon planiscapus
Some varieties of Ophiopogon planiscapus remain green with paler edge stripes. Source: Starr

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’

Ophiopogon japonicus
Ophiopogon japonicus stays a lush green and has narrower leaves. Source: vikisuzan

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 densely plant.

Ophiopogon intermedius, ‘Aztec Grass’

Aztec grass
Aztec grass grows much larger than lilyturf. Source: cultivar413

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

Black lilyturf
This lowlying plant grows to 8-12″ in height. Source: brewbooks

But how does one care for black mondo grass? 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, but it should be a “cool sun” condition. If you’re in a hot, desert-like climate, afternoon shade is preferable.

It’s 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.

During the first year after planting, water 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. Opt for something which sets off the look of the grass-like leaves well, like a contrasting wood chip.

It’s 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 soil which is well-draining is best for your 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 easily penetrate.

Excess water needs to drain away to prevent root damage. Avoid muddy conditions!

Fertilizer

Fertilizing should be rare for this plant. A spring application of compost around the plant’s base should be more than enough to feed it.

Propagation

Black mondo berries
Small berries form after the flowers fade. Source: MTSOfan

While black mondo will spread, its spread is very slow. It’s much easier to divide off new plants in the spring.

Remove a large clump of mondo 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 their own roots and leaves.

Once separated, you can replant at 4″ intervals to provide a good cover.

You can grow mondo grass from seed, 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 mondo. 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 plants will thrive. But what if they’re not performing right? Let’s troubleshoot.

Growing Problems And Diseases

Root rot in mondo
Root rot can cause yellowing and browning of mondo leaves. Source: happy via

The biggest problem you’re likely to face is root rot, particularly pythium root rots. This fungal rot can develop when soil is too moist, causing yellowing and browning of leaves. If not treated, it can lead to 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 plant wilting. If the soil is dry more than an inch below the surface, it’s time to water. Consider adding mulch to slow evaporation of soil moisture.

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!

But there’s two that don’t, both related: snails and slugs. These can chew holes in leaves, or gnaw the leaves right off. 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 plant. 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 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 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 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.


The Green Thumbs Behind This Article:

Lorin Nielsen
Lifetime Gardener

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