Monkey grass is one of those plants you have probably walked past a thousand times without knowing its name: the tidy, dark-green tufts edging a sidewalk, the carpet of strappy foliage under a shade tree, the soft border tracing a flower bed. It is tough, evergreen in most of the country, shrugs off drought, deer, and salt spray, and asks for almost nothing in return. But there is one decision you have to get right before you buy a single plant, because one type behaves itself for decades and the other can quietly take over your yard. This guide walks through both, plus how to plant, the single maintenance chore that matters, and how to pull it back out if it ever escapes.
What monkey grass actually is (and why it is not a grass)
Despite the name, monkey grass is not a grass at all. It belongs to the genus Liriope in the asparagus family (Asparagaceae), the same broad family that includes hostas and, yes, edible asparagus. It is a clump-forming, grass-like evergreen perennial with long, narrow, arching blades, spikes of small purple (sometimes white) flowers in mid- to late summer, and clusters of blue-black berries that follow. You will also hear it called lilyturf, border grass, and spider grass.
The name confusion runs deeper. “Monkey grass” is used loosely for two completely different plants:
- Liriope (lilyturf) — the wider-bladed, taller, clump-forming plant this article is about.
- Mondo grass (Ophiopogon japonicus) — a separate genus with finer, thinner, darker leaves that forms low, dense mats. Mondo grass is shorter (roughly 3 to 12 inches) than liriope (10 to 18 inches) and carries blue berries rather than black ones.
Both are in the asparagus family, both are grass-like, and both get called “monkey grass” at the garden center, which is why so many people end up with the wrong plant. If you want the real edging-and-border workhorse, you want Liriope. The quickest field test: liriope has noticeably wider blades and grows in taller, fuller clumps; mondo grass is fine-textured and hugs the ground.
The one buying decision that matters: clumping vs spreading
Almost every problem people have with monkey grass traces back to buying the wrong species. There are two in common use, and they behave nothing alike.
Liriope muscari — the well-behaved clumper
Liriope muscari, often sold as “big blue lilyturf,” grows in neat, self-contained clumps. It expands slowly outward by short stolons rather than running underground, so it stays roughly where you put it. Blades are wider (about 3/8 to 1/2 inch), it reaches 10 to 18 inches tall, and it produces the showiest flowers of the two: dense lavender-to-violet spikes held above the foliage, followed by black berries. This is the one you want for edging, borders, foundation plantings, and any spot where you need it to hold a line. Popular cultivars include the reliable ‘Big Blue’, the white-flowered ‘Monroe’s White’ for shade, the tall, stiff-bladed ‘Evergreen Giant’, and variegated forms such as ‘Variegata’ and ‘Silvery Sunproof’ (the latter handles more sun than most variegated types).
Liriope spicata — the spreading runner (use with caution)
Liriope spicata, “creeping lilyturf” or creeping monkey grass, is a different animal. It spreads aggressively by underground rhizomes and will keep going indefinitely, knitting together into a dense mat that covers ground fast. Its blades are narrower (about 1/4 inch) and its flowers smaller and paler. That running habit makes it excellent for blanketing a slope, controlling erosion, or filling a large, difficult area where you genuinely want full coverage and nothing else growing. The same habit makes it a poor choice for edging — it will not respect a border — and a genuine problem if you plant it casually. In parts of the Southeast and other regions, L. spicata has jumped garden beds into natural areas and is treated as invasive. Plant it deliberately, give it hard edges (more on that below), and never set it loose where it can creep into a lawn, a neighbor’s yard, or a woodland edge.
Quick rule of thumb: if you want an edge or a border that stays put, choose L. muscari. If you want to cover a large bank or slope and are prepared to contain it, choose L. spicata.
Where monkey grass will grow
Part of the appeal is how little it cares about conditions. Monkey grass is genuinely one of the most adaptable ornamentals you can plant.
- Light: Full sun to deep shade. It is one of the few groundcovers that thrives in dry shade under trees, but it flowers most freely in a sunnier spot. Foliage tends to be darker green in shade and can pale slightly in strong sun.
- Soil: Almost anything that drains — sand, loam, or well-drained clay. It prefers slightly acidic soil around pH 6 to 7 but is not fussy. The one thing it will not tolerate is “wet feet”: soggy, poorly drained ground is the fast track to root and crown rot.
- Hardiness: Roughly USDA zones 5 to 10. It stays evergreen through mild winters; in colder zones the foliage may tatter or brown by late winter, which the annual cleanup fixes.
- Toughness: Once established it is drought tolerant, tolerates heat, and even shrugs off coastal salt spray, making it useful in seaside gardens where many plants scorch.
How to plant monkey grass
Plant in spring or fall. Loosen the soil, work in a little organic matter if your ground is poor, and set each plant so the crown (where the blades meet the roots) sits right at soil level — never bury the crown, which invites rot. Water in well and keep the soil moist, not soggy, while roots establish.
Spacing depends entirely on the look you are after:
- For edging or a defined border (L. muscari): Space plants about 10 to 12 inches apart. They will knit into a continuous ribbon within a season or two while staying as a clean line.
- For solid groundcover coverage: Space closer, around 8 to 10 inches apart, so the clumps merge quickly into an unbroken carpet. Closer spacing means faster fill but more plants; wider spacing is cheaper but leaves gaps to weed for a year or two.
- For erosion control on a slope (L. spicata): You can space a bit wider, 12 inches or more, and let the rhizomes do the filling for you.
Mulch lightly between new plants to suppress weeds and conserve moisture while they establish. Keep mulch off the crowns.
Watering and feeding
For the first growing season, water whenever the top inch or two of soil dries out. Moist soil drives the root spread that gets the planting established. After that first year, monkey grass becomes notably drought tolerant and usually gets by on rainfall, needing supplemental water only during prolonged summer dry spells — and even then, water in the morning so the foliage dries quickly.
Feeding is almost optional. Monkey grass grows fine in poor soil and rarely needs fertilizer. If you want to push growth or refresh a tired planting, scatter a balanced slow-release fertilizer (such as 10-10-10) around the plants in early spring. Two cautions: do not over-fertilize, and keep granules from lodging down between the blades against the crown — both stress the plant and make rot more likely.
The one chore that matters: shear it back in late winter
If you do nothing else, do this. Over the year, the old blades brown at the tips and the whole planting starts to look tattered, especially after winter. The fix is to cut off all the old foliage once a year, in late winter or very early spring, just before new growth pushes up — roughly late January to mid-February in the warm South, a little later farther north. New leaves emerge within a few weeks, and the planting comes back fresh, green, and full.
How to do it:
- For a small border, sharp shears or hedge trimmers are fine. For a large planting, a lawnmower on its highest setting or a string trimmer makes quick work of it. Cut down to about 3 inches.
- Do not scalp the crowns. Set the mower high and keep the blades sharp so you slice cleanly rather than tearing. Cutting too low damages the crowns the new growth comes from.
- Mind the timing. If you wait until new shoots have already emerged, you will clip the fresh, rounded leaf tips and the planting looks blunt all season. If that happens, cut by hand around the new growth instead of mowing.
This single cut does double duty: it removes the ragged old foliage and it clears away last year’s leaves, where fungal diseases like anthracnose overwinter. Raking up and removing the clippings afterward is part of the job, not an afterthought.
Dividing and propagating
Monkey grass clumps thicken over time, and every three or four years you may want to divide them — to rejuvenate a congested clump, or simply to make more plants for free. Division is rarely needed for the plant’s health; it is mostly about spread and propagation.
In early spring or fall, dig up a clump, knock off the loose soil, and pull or cut it apart into smaller sections, each with a healthy fan of blades and roots attached (aim for at least three to five shoots per division). Replant immediately at the same depth, water well, and keep moist until you see new growth. Division is by far the easiest way to propagate. You can grow it from seed harvested from the ripe black berries, but it is slow and finicky, so most gardeners stick with dividing.
Flowers, berries, and what eats (or avoids) it
From roughly July into early fall, monkey grass sends up spikes of small but showy lavender, purple, or white flowers — L. muscari puts on the better show — followed by clusters of blue-black berries that persist into winter and add quiet interest. The plant is not considered toxic to dogs, cats, or people; the asparagus-family foliage is on standard non-toxic lists, though a pet that gorges on any greenery may get a passing upset stomach.
Just as useful: monkey grass is reliably deer and rabbit resistant. Its tough, fibrous blades hold no appeal, which makes it a go-to groundcover and edging in gardens where browsing wildlife shreds everything else.
Design uses
This is a remarkably versatile plant in the landscape:
- Edging and borders — L. muscari makes a soft, evergreen line along walks, driveways, beds, and the front of foundation plantings; far easier than mowing a strip edge.
- Mass groundcover — sweep it under trees and shrubs where lawn won’t grow, or carpet a shady bed.
- Dry shade under trees — one of the few things that genuinely thrives there.
- Between pavers and steppers — a low green seam in patios and paths.
- Erosion control on slopes — L. spicata‘s dense, knitting rhizomes lock soil on banks and hillsides too steep to mow.
- Lawn alternative — in low-traffic areas, a planting you mow once a year instead of weekly.
Common problems and how to handle them
Monkey grass earns its low-maintenance reputation, but a few issues show up — almost all of them tied to too much water.
- Crown and root rot — the most serious problem, caused by water-mold and fungal pathogens (Phytophthora, Fusarium, Rhizoctonia) in soggy or poorly drained soil. Inner leaves yellow, then the bases brown and the plant collapses; dug-up roots look dark and slough their outer tissue. Fungicides only slow it. The real fixes are cultural: plant in well-drained soil, never bury the crown, do not over-mulch or over-fertilize against the crown, and remove and dispose of affected plants promptly so it does not spread.
- Anthracnose / leaf spot — reddish-brown spots along leaf margins and tips, caused by Colletotrichum, worse with frequent rain or overhead watering. The fungus overwinters in old foliage, which is exactly why the late-winter shear-and-clean-up matters. Avoid overhead and late-day watering, thin congested clumps for airflow, and remove diseased debris.
- Liriope scale — small, immobile insects that cause yellow or reddish spotting and dieback. Cutting back the foliage in late winter and clearing the clippings removes a lot of the population; for heavier infestations, a thorough horticultural oil spray after that pruning, timed to hit the vulnerable crawler stage, gives good control.
- Slugs — can chew the foliage, especially in damp shade. Reduce hiding spots, water in the morning, and use bait or traps if damage builds.
Notice the through-line: good drainage, morning watering, airflow, and that one annual cleanup head off nearly everything.
How to contain it — and how to get rid of it
If you are planting the spreading L. spicata on purpose, contain it from the start. Sink a hard edge — deep landscape edging, a buried barrier, or a mowed strip and paved boundary — around the planting before it runs, because pulling it back later is real work.
To remove monkey grass that has spread where you don’t want it, dig it out: lift the clumps and chase out as many of the rhizomes and roots as you can, because any fragment left behind will resprout. For a stubborn or large patch, smother the cleared ground with landscape fabric or thick mulch to block the light that fuels regrowth, and stay diligent — strays will keep poking up for a season or two, so pull them as they appear. A systemic herbicide painted onto the new regrowth can finish off persistent runners. It usually takes more than one pass, but between digging, smothering, and spot-treating the regrowth, you can win.
Monkey grass is, for the most part, a plant you put in and forget — give it well-drained soil, the right species for the job, and one good haircut a year, and it will hold its line, fill its space, and stay green long after fussier plants have given up.