Gardening & Outdoors

The Ultimate A-Z Black Mondo Grass Gardening Guide

If you are anything like me, you've probably mulled over which low growing plant you should use to spice up your garden when overlooked by high growing plants. Or, maybe you need a ground cover plant for accents around your rock garden.

The Ultimate A-Z Black Mondo Grass Gardening Guide

You should consider Black Mondo grass, which although spread gradually is striking when massed along edges. Perhaps the blackest plant of all, it forms low growing clumps of slender strap like softly shining black leave.

Growing 6-10 inches in height, it spreads by underground runners which launch additional "black spiders" around the parent plant. Short black stems produce conspicuous mauve-white summer flowers which develop into round blackberries.

Black mondo grass distinctive black foliage provides a dramatic contrast with lightly colored plants soliciting a lot of comments. I mean, how many leafy plants do you know have a rich black shade?

If you are looking to add dramatic themes with black mondo, below is the ultimate A-Z black mondo gardening guide.


Now that you are considering black mondo grass, I bet you are wondering how to grow it, right?

Start black mondo Grass seeds indoors in the early spring. Use small pots filled with seed starting mix. Place the ornamental grass seeds onto the soil and cover thinly with sand or soil and keep the seeds moist. Transplant outdoors once soil temperatures have warmed and frost danger has passed.

Once planted, young leaves grow into neat, slow spreading 4 quarter inch sweetly fragrant, strap-like vessels.

New foliage emerges green in spring which darkens to purplish black in summer. It will develop small lilac blooms followed by shiny black berries that persist through the winter. Healthy plants have a shininess to them that should remain all year long.

The plant will grow 2 feets slow crumping spread which will eventually fill to create a lush, blackish carpet.


Preparing Black Mondo Grass Seeds

  1. Harvest the seeds when they are completely black (mature). You can check by turning the seed pod over. If the seeds still have a green tinge give them more time to ripen. The seeds usually mature between October- November, if sure the seeds are ripe knick a few from each plant.
  2. After harvesting peel the seeds by squeezing between your thumb and forefinger. Alternatively, use a spoon to squash on a tabletop.
  3. Once squashed remove the peel and wash the seed clean. Later, soak the seeds for a couple of days, make sure to change the water regularly. Soaking the seed in water helps speed up germination.
  4. Start germinating the black mondo seeds indoors in the early spring. Place them in soil and cover thinly making sure to keep the seeds moist. Grow the seed at 60F, If after 3 weeks there is no germination place the container at 40F for 3 - 4 weeks later move them back to warmer temperature, germination should take between 30 and 150 days.
  5. Start germinating the black mondo seeds indoors in the early spring. Place them in soil and cover thinly making sure to keep the seeds moist. Grow the seed at 60F, If after 3 weeks there is no germination place the container at 40F for 3 - 4 weeks later move them back to warmer temperature, germination should take between 30 and 150 days.

Use trays to plant the seeds 2cm apart. Cover with a thin soil-compost mix and place the trays in a cool room. Use a cold frame when available and if you choose to put the seeds outdoors cover them with chicken wire for protection against curious animals.

Preparing the Garden Soil

New beds for black mondo grass should be properly prepared before planting to ensure rapid establishment and minimal weed problems.

Black Mondo grass requires well-drained slightly acidic (pH 5.5-6.5) loam soil rich in organic matter. To reduce weeds before transplanting, apply a slow-release fertilizer (containing nitrogen, phosphorus, and potassium) at 1⁄2 lb nitrogen per 1000 square feet and water the surface for two weeks. This will encourage weeds to grow which you will later eliminate with a contact systemic herbicide. After 7-10 days of spraying, the weeds will die.

Make a second application of a complete fertilizer and cultivate it into the soil to a depth of 5–6 inches. This time add soil amendments such as compost, and if the soil is too acidic (pH less than 5.5), agricultural lime

Rake the area level and water again for about two weeks to germinate weed seeds brought to the surface by the cultivation. When the second round of weeds has been killed with herbicide, the soil should be relatively free of weed seeds and prepared for transplanting.

If you want to plant black mondo grass in containers, use a good quality potting mix with good drainage.

Transplanting Black Mondo grass

Once you are done preparing your garden leave the plants in their trays until spring. When its time plant the seedlings in holes that can accommodate the root balls.

Keep the distance between each seedling at between 3-8 inches (7-20 Cms). Black mondo grass is self-propagating with substantial lateral growth which will eventually fill the spaces between the seedlings while mature. Always keep the soil moist till the plants establish.


According to the College of Tropical Agriculture and Human Resource, the fleshy, tuberous root system of mondo grass gives it a very good tolerance of full sun and drought conditions. However, it grows much better when it receives partial to full shade and the soil is well drained and kept consistently moist.

Although black mondo grass does well without fertilizer, use light application through spring and summer to maintain color and appearance without prompting excessive growth. Use organic, controlled- release or compost fertilizer for best result without injuring the crowns.

Spread 1/2 compost top dressing annually on the mondo grass to encourage the lateral spread of rhizomes and provide micronutrients. Compost is particularly beneficial during the first several growing seasons and will shorten the time to reach full cover.

Mowing mondo grass once or twice during the first few growing seasons stimulates growth, but this temporarily reduces the size of the individual clumps, and the cut ends of the leaves may look unattractive until new leaves grow. Set your mower in high to go easy on the grass substantially reducing scalping risks. Opt for a stiff hand rake to remove dead leaves periodically.

Weed Control

The growth of annual weed is minimal when the grass has spread to cover the entire surface. However, Black mondo and other slow-growing varieties may never completely cover the area to choke out weeds.

Use pre-emergence herbicides to prevent emergency of grasses and broadleaf weeds. Use the herbicides before planting and on regular occasions on established plants.

Some perennial weeds can be controlled using postemergence herbicides but will injure the plant if accidentally over sprayed.


The most serious disease of mondo grass is root rot caused by Pythium splendens. The first symptoms of are normally circular spots, usually between 2-5cm, which can reach up to 15 cm. The spots appear suddenly during warm to hot humid weather.

Leaves in these patches appear water-soaked and dark in the early morning. If these water-soaked spots are rubbed between the fingers they feel slimy.

Onset leaf tips turn bronze-brown which progress to the whole leaf structure. Eventually, the crown will easily separate from the base when gently pulled.

Pythium Splendens is a water-borne disease that thrives in rainy weather with warm nights (68F/20Celcius) and hot days (86F/30Celcius). It's present in heavy-poorly drained soil associated with additional watering during seeding.

The soil-borne Pythium is difficult to control, but there are some fungicides labeled for drench application to mondo grass. Topdressing with compost may also help because it improves competitive soil microflora populations.

Avoid overwatering your black mondo grass. Soggy soils help Pythium to thrive. Consider changing your watering schedule each season.

Sometimes, you will plant mondo grass in Summer (71.9F/22.2Celcius) when the moisture in the soil is not much, the grass will do well for a few months till Autumn (53.9F/12.2Celsius) then the leaves will start changing color and slowly die off.

On wetter seasons water doesn't evaporate as fast, make sure to adjust the watering periods through the seasons.


Scale Bugs

The main insect problem with mondo grass is scale. Although this insect does not cause serious damage, it does cause unsightly specks on the leaves and rob the plant essential nutrients. Scale bugs can be checked by spraying oil-based insecticides like neem oil labeled for ornamental grass.

To eliminate scale bugs from indoor black mondo plants dab each scale with a piece of alcohol-soaked cotton.

Common Garden Snails & Slugs

The slugs & snail will chew through the tender leaves of plants making them unsightly. To reduce garden snail and slugs use snail granules which contain ferric phosphate.

Put on a pair of gloves, and evenly sprinkle the slug and snail bait granules on moist soil near the mondo grass, so that the granules lie 1/4 to 1/2 inch apart.

Alternatively, make gritty surfaces which will cut or injure the snail. Sprinkled eggshells or sand around plants to deter and eventually kill these pests.

You may as well set out traps, like beer pans. Simply fill a shallow pan with beer and leave it out overnight. The snails will be attracted to the beer and drown in it.

Introduce predators in the garden, but this is a few more animals to worry about. Toads effectively reduce slugs population, If not worried of a little slither around the yard bring in small poisonous snakes, which are to slugs what a cat is to rats.

Black Mondo Growing Conditions and Zones

Black mondo will thrive with full sun in places getting 6 or more hours of sunlight. It does equally well in partial shade with 2 to 4 hours of sun in a day.

This makes it perfect for transition zones where gardens change from sun to shade. This transition zone stretch from the Central Atlantic Coast South of Philadelphia through the mid-west and mid-south states to the Nothern parts of Louisiana terminating in North East New Mexico.

The Cool/Humid zone in the Northwest receives a great deal of moisture which is problematic to Black Mondo.

The cool/humid section in the northern half of the Mid-West extending throughout the Northeast has hot summers and very cold winter, black mondo grown in this areas has to be protected from cold winter weather. Pile woods mulch over the grass to insulate and keep the ambients temperature around the grass warm.

Black Mondo does well in a range of conditions, stretching from hot, warm and cool states. Zone 6 through 10 culture the perfect conditions

In zone 5 black mondo should be planted in protected areas. With heavy winter frosts and snow, the plants will die back in winter but will come up in spring from the roots, black mondo will only survive in Zone 5 but won't thrive.

Ultimately black mondo grass will grow across the globe in areas with weather pattern (and ideal soil quality) akin to Zone 6-10 of the USDA hardiness zones, and AHS plant heat zone 12-1.

What Goes with Black Mondo Grass

Contrast with Coral Bell (Caramel Heuchera)

You should consider contrasting the dark black mondo hue with a uniquely lobed foliage, emerging grey-red in spring and maturing to apricot-red with burgundy undersides by summer.

The hardy Caramel Coral Bell will delicately tower broadly while black mondo gradually creeps extending half the leaves to peep beautifully underneath the contrasting drapery.

The contrasting foliage will hug to create a facade of varying colors and height. Top that with a variety of green Japanese Hakone grass and you've got yourself a natural stunner.

Gild it with Chartreuse ( Hakone Grass)

When gold (Hakone grass) is not naturing the contrast above (contrast with coral bell), You can use it independently (or any chartreuse variant like Carex) to device a baffle.

Hakone is the ultimate ornamental grass. It adds a beautiful goldish- green touch to black mondo, which transition each season. It poses an outstanding chartreuse fall color changing to exquisite copper -orange shades before taking a bow in winter.

Hakone foliage form attractive mounds of gracefully arching leaves that shimmer in unison with the black mondo glow.

Dark-Glamour-Drama (Purple Millet & Purple Heart Plant )

Confine black mondo grass in a vase, and let it slowly spread through the breaths of the container. Relish the elegant facade with other purple plants to achieve a dark dramatic theme.

Add in some purple millet to refine the black mondo tune. The purple millet crown texture will decently culture the slender mondo foliage.

Blend with purple heart plant (zone 7-11) for broader leaves layout inside the ground cover section.

Touch up with A Soft Green Moss Mat (Scotch Moss)

This aspect taps the true beauty of black mondo, it towers over the expanse of the moss mat forming an impressive silhouette.

There is a sharp brilliant contrast between the dark grass and the lush chartreuse to yellow moss-like foliage, slightly like the crown on a pineapple.

Foliage with a Silver Lining (Dusty Miller)

Between zones 4-9? You've got yourself some silver. Ideal in pots and borders, dusty miller tune-up with black mondo to bring a priceless show

Both plants are ideal to break a cliche in a way that stands out. Whether inside rows or edges dusty miller is the "moon" in black mondo "nights"

A Curious Blue Mash-up(Blue Fescue)

Form a border with alternating black mondo and blue fescue (Elijah Blue), for calm dramatic illusions.

Preferably plant the mash-up in adjacent steps on an ascending bed massed with other aspects.

The sparkle of blue fescue and the subtly in black mondo will aid in creating perfect transition a step a time.

The resulting impression would be close to the one made in a Phormium Amazing Red and blue fescue mix just a little shorter perfect for zone 4-11

When to Grow Black Mondo Grass

Turf grass historically has been the most common ground cover in many climates. But these days concerns about water conservation and climate change have led gardeners and designers to turn to environmentally friendly lawn alternatives

With lower maintenance need mondo grass including black mondo to fill that loop. Mondo grass hold up decently in partial shade unlike most turfgrass varieties

This ground cover plant can endure light foot traffic and more with stepping installed on pathways.

Black mondo grass is perennial with admirable longevity all year long. The foliage built landscape definitions and structure allowing lawns traits to standout

Black mondo does well both in pots and gardens. Best used for edges, ground cover, mixed borders, rock gardens, under trees and along pathways.