How to Grow and Care for Monkey Grass (Black Mondo Grass or Lilyturf)

Close up of black monkey grass used in a landscape

David Beaulieu

"Monkey grass" is a common plant name you are most likely to hear in the Southern U.S., and it can refer to two different plant groups: Ophiopogon (including black mondo grass) and Liriope (including lilyturf). While they look somewhat similar and are used in similar ways in landscaping, these perennials are, in fact, two totally different plants. Either one (or one of their close relatives) is a good option for a shade-tolerant, semi-evergreen ornamental grass.

Black Mondo Grass

Black mondo grass (Ophiopogon planiscapus 'Nigrescens') is a tuberous-rooted perennial in the lily family. It is a stemless plant in which the leaves sprout from the ground in clumps. In summer, a single flower stalk sprouts, carrying small, bell-shaped pinkish flowers. This grasslike plant is often used as a ground-cover for semi-shady areas, or in the front of borders or as edging plants. It is common in rock gardens.

  • Botanical name: Ophiopogon planiscapus 'Nigrescens'
  • Common name: Monkey grass, black mondo grass
  • Plant type: Herbaceous perennial
  • Mature size: 9 to 12 inches in height with a similar spread
  • Sun exposure: Full sun to part shade
  • Soil type: Rich, moist but well-drained.
  • Soil pH: Slightly acidic; 5.5 to 6.5
  • Bloom time: July to August
  • Flower color: Pink
  • Hardiness zones: 6 to 9 (USDA)
  • Native area: Japan

How to Grow Black Mondo Grass

Space the plants about 4 inches apart, planting them in moist, well-drained soil, and immediately top-dress them with a layer of compost to help retain soil moisture. No seasonal feeding is needed. Each spring, remove the old foliage from around the plants. Where you want to thin the plants or propagate them, lift and divide the roots in spring. There are few pest and disease problems, but you may need to protect them against slugs and snails.

Light

Black mondo grass tolerates a wide range of sun conditions, but the warmer the climate, the most that shade is of benefit.

Soil

This plant prefers a moist but well-drained soil that has ample organic material. The ideal pH is somewhat acidic.

Water

Mondo grass needs to be kept consistently moist but not soggy. The hotter the temperature, the more water is required.

Temperature and Humidity

Ideal growing conditions are warm but not hot. This plant tolerates a wide range of humidity levels, provided the soil can be kept moist. Moist climates may see slugs and snails as a problem.

Fertilizer

Black mondo grass does not require much in the way of feeding. A single top-dressing of compost in the spring will suffice.

Propagating Black Mondo Grass

Black mondo grass is usually propagated by lifting and dividing the fibrous roots in spring.

  1. Use a garden fork to pry clumps up from the ground.
  2. Use your hands to tease apart groups of roots, dividing them into sections each containing a few leaves. A knife or sharp trowel may be necessary if the roots are thickly entwined.
  3. Cut away any dried or diseased portions of roots.
  4. Replant the clumps about 4 inches apart in the garden. If you cannot plant them right away, make sure to keep them moist until planting.

Lilyturf

Lilyturf, the other plant commonly known as monkey grass, includes two species: Liriope spicata (sometimes called creeping liriope, as well as lilyturf) and Liriope muscari (which also goes by the common name of big blue lilyturf). Lilyturf has very similar a very similar growth habit and landscape use to black mondo grass, but it is a slightly taller plant.

  • Botanical name: Liriope spicata or Liriope muscari
  • Common name: Lilygrass, monkey grass
  • Plant type: Herbaceous perennial 
  • Mature size: 9 to 18 inches
  • Sun exposure: Full sun to part shade
  • Soil type: Average, well-drained
  • Soil pH: Neutral to slightly acidic; 6.0 to 7.0
  • Bloom time: August to September
  • Flower color: White to lavender
  • Hardiness zones: 4 to 10 (USDA)
  • Native area: China, Japan, Southeast Asia

How to Grow Lilyturf

Plant lilyturf in any medium, well-drained soil, spacing them about 12 to 18 inches apart; the plants will quickly fill in gaps. Poor soil should be amended with compost. Feeding is rarely necessary; an annual top-dressing of compost may be helpful. Once established, water the plants deeply once a week. Where division is necessary to thin out dense clumps or propagate plants, do it in the early spring. The foliage can be mown down with a lawnmower set at a high cutting length when the growing season is over (in warmer climates, the plant may be evergreen). In the northern end of the hardness range, make sure the plants are covered over winter. Lilyturf is very easy to grow and has few pest or disease problems, other than slugs and snails. However, L. spicata can be an aggressively invasive plant, so watch it to prevent it from naturalizing out of your yard.

Light

Lilyturf tolerates a wide range of sun conditions, but the warmer the climate, the most that shade is of benefit.

Soil

This plant prefers an average, well-drained soil that has ample organic material. The ideal pH is somewhat acidic.

Water

Lily grass performs ideally if it receives a good, heavy watering each week, but once established it has good drought tolerance.

Temperature and Humidity

Ideal growing conditions are warm but not hot. This plant tolerates a wide range of temperature and humidity levels. Moist climates may see slugs and snails as a problem.

Fertilizer

Lilyturf does not require much in the way of feeding. A single top-dressing of compost in the spring will suffice.

Propagating Lilyturf

Lilyturf is usually propagated by lifting and dividing the fibrous roots in spring.

  1. Use a garden fork to pry clumps up from the ground.
  2. Use your hands to tease apart groups of tubers, dividing them into sections.
  3. Cut away any dried or diseased portions of roots.
  4. Replant the clumps about 12 to 18 inches apart in the garden