Growing Black Mondo Grass and Lilyturf

The Story Behind Monkey-Grass Madness

Black monkey grass can create contrast in a landscape design as this photo shows.
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 Characteristics

Black mondo grass (Ophiopogon planiscapus 'Nigrescens'), like Liriope, looks very much like an ornamental grass. But for all their grassy looks, neither of these perennials is a member of the Poaceae family (that is, the true grasses). In fact, both belong to the Ruscaceae family.

What strikes one immediately about black mondo grass is that the adjective in its name is no exaggeration. The foliage is actually black, rather than deep purple, like many so-called "black plants." Black mondo grass may also produce pinkish-lavender flowers, which are followed by purplish-black berries. This means that it's technically a flowering ground cover. But for most people, all of this takes a back seat to the unusual evergreen to semi-evergreen foliage. It grows to be 6 inches tall and has a clumping habit.

Growing Black Mondo Grass

Many list black mondo grass for USDA plant hardiness zones 6 through 9. However, the label that some plants come with list it as zone-5 hardy. Many zone-5 gardeners can attest to its ability to survive there. If you have concerns about the cold, your can apply mulch to give it winter protection. As time goes by, your plant may even produce off-shoots.

Black mondo grass is a slow grower. Divide it in spring, if desired. In early spring, trim off any leaves that have become ratty-looking over the winter, before the new growth comes. More severe spring haircuts may be called for when trimming older plants.

Another tricky issue for beginners to black mondo grass is its need for sunshine. If southern climates, it is typically treated as a shade plant, because intense sunlight in warm climates will fade its trademark color. Northerners, meanwhile, can grow it in full sun.

But regardless of where you live, the claim that it is "shade tolerant" is justified. It prefers fertile, evenly-moist, well-drained soil but will tolerate some drought once mature. Those in deer country can add it to their list of deer-resistant ornamental grasses with which to keep Bambi at bay.

Landscape Uses for Black Mondo Grass

Black mondo grass makes for a good edging plant. If you have anything at all of a designer's eye, the dark color of the plant's leaves will bring out the artist in you. Design possibilities are endless, but you may especially enjoy creating contrasts by placing black mondo grass next to plants that sport bright colors. For example, if you grow yours in full sun, partner it with 'Angelina' sedum for contrast. Scotch moss (Sagina subulata 'Aurea') would also work here.

If you grow black mondo grass in partial shade, try pairing it with a bicolored hosta. In this case, you'll also create a contrast of plant textures. Black mondo grass has a fine texture, while hosta is coarse.

Other Types of Ophiopogon

A plant in the same genus as black mondo grass and just as shade-tolerant is Ophiopogon japonicus (zones 6-9). It can reach 6-10 inches in height, although dwarf types also exist (for example, the 'Kyoto Dwarf' stands 2-4 inches tall). Not as showy as black mondo grass, this plant makes up for it by being useful as a ground cover.

O. japonicus will spread, which is a double-edged sword. Its ability to spread can make this less showy monkey grass invasive, but that same ability enables you to grow it as an alternative to lawn grass. As such, it can be used to form a shade-tolerant "lawn." Lovers of low-maintenance landscaping, take note: This is a lawn that you'll never have to mow.

Its tendency to spread allows it to serve other purposes as well. You can plant it between the cracks of garden stepping stones (some use creeping thyme for this purpose). It spreads via underground rhizomes, making it good for soil erosion control. Finally, many homeowners struggle with the problem of how to plant under trees, and tough plants such as O. japonicus often provide a long-sought solution.

Growing Lilyturf

Lilyturf, the other "monkey grass," includes two common types:

  • Liriope spicata
  • Liriope muscari

Liriope muscari offers more ornamental value and is popular in the South, but it isn't as hardy as Liriope spicata (suitable for zones 4-10). One advantage that Liriope spicata has over black mondo grass is that its flowers are showier because the flower stalks rise farther above the foliage than those on black mondo grass. The latter's flowers are sometimes hidden by the foliage. Some types of Liriope also boast variegated leaves.

Lilyturf is used in the same ways as Ophiopogon. In fact, its use as an edging plant led to the nickname, "border grass." Like O. japonicus, it spreads. Being the faster grower of the two "monkey grasses," its potential for invasiveness is greater.