Black mondo grass
Ophiopogon planiscapus 'Nigrescens' · Asparagaceae
Arching, strap-shaped leaves that are truly black, with small pale pink flowers and shiny black berries. It spreads very slowly.
- Size
- 8 in tall, 12 in wide
- Zones
- 6 to 9
- Light
- Full sun to part shade
- Flowers
- Grown for its leaves; flowers early July to early August
- Pets
- No toxicity recorded
- Job in a bed
- Edging
A bed built around black mondo grass
The planner designed this bed around black mondo grass when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why black mondo grass stands where it does.
The plants
- 1 Black mondo grass × 18, black leaves
- 2 Spotted dead nettle 'White Nancy' × 5, white
- 3 Brown-eyed Susan × 5, yellow
- 4 Astilbe 'Purple Candles' × 5, purple
- 5 Deutzia 'Chardonnay Pearls' × 1, white
- 6 Hyacinth 'Delft Blue' × 10, blue
- 7 Autumn crocus × 12, lavender
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
Why here
- Near the front. At 8 in it is the step between spotted dead nettle 'White Nancy' (6 in) in front and deutzia 'Chardonnay Pearls' (2½ ft) behind: each is seen over the one before.
- 18 plants in 4 groups (7, 5, 3 and 3). Seen again further along, the same plant ties the bed together.
Why now
- Here for its leaves, all year. They cover the 12 weeks between early March and late November when nothing on the plan is in flower.
- The only leaves in winter. From November to March it is what there is to look at.
Planned as a cottage garden: 27 of the 34 plants (79%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. It is planted in layers: about 8 in at the front, 18 in in the middle and 3½ ft at the back. Black mondo grass is the plant there is most of: 18 of the 56.
The planner's own design check: 9 Excellent, 7 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where black mondo grass goes in a border
At 8 in it belongs at the front of a bed. In the planner's ten height classes it is low (6 to 12 in).
Its job: edging. A low, neat plant used in short runs of three or five along the front to finish the edge (or, in a formal bed, in one even row).
The blackest plant in the garden. It disappears against bare soil, so give it a pale background: gold Japanese forest grass, chartreuse leaves or light gravel.
- Black foliage for contrast
- Edging and containers
- Modern and Japanese-style gardens
What to plant with black mondo grass
Plants recorded as good partners for it, and what each pairing does:
- Japanese forest grass 'Aureola': tall enough (16 in) to stand behind it.
- Hosta 'June': bold leaves against its fine ones; a low mound at the foot of its spires; tall enough (16 in) to stand behind it.
- Coral bells: a low mound at the foot of its spires.
Questions about black mondo grass
Does black mondo grass need sun or shade?
Black mondo grass grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells.
What zones does black mondo grass grow in?
USDA zones 6 to 9. It is hardy to zone 6, which means it survives winter nights down to about 0 °F (−18 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should black mondo grass be planted?
8 in (20 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 12 in (30 cm), so a group knits into one patch.
It grows 8 in (20 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many black mondo grass plants do I need?
At 8 in apart, set out in staggered rows:
- 27 to fill 10 square feet (about 1 m²)
- 16 for a single row 10 ft (3 m) long
- 86 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as runs of three or five along the front (or one even row, in a formal bed).
In the bed above, the planner used 18 in four groups.
Is black mondo grass poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like black mondo grass?
Black mondo grass comes from Japan. These North American natives come closest to doing its job:
- Coral bells 'Firefly': the same job in a bed and the same size; flowers late May to late July, medium leaves, not fine.
- Bristleleaf sedge: the same job in a bed and the same size; not evergreen.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat black mondo grass?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
What does black mondo grass look like in winter?
Black mondo grass keeps its black leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
More Ophiopogon
- Mondo grass Ophiopogon japonicus
In these guides
Every fact on record
- Type
- Perennial
- Size
- 8 in (20 cm) tall, 12 in (30 cm) wide
- Plant
- 8 in (20 cm) apart
- Height class
- Low (6 to 12 in)
- Place in the bed
- Front
- Flowers
- Early July to early August; upright spires; pink
- Leaves
- Fine texture, evergreen; black
- Shape
- Arching, spreading
- Hardy in
- USDA zones 6 to 9
- Light
- Full sun, part sun, part shade
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Asparagaceae
- Comes from
- Japan
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.