The main disadvantages of mondo grass are slow growth, high cost, and poor foot traffic tolerance. These drawbacks won't ruin your yard, but you need to plan ahead before you commit to a big planting area.
I planted a 200 square foot patch of mondo grass in my side yard three years ago expecting it to fill in by fall. That first season was painful. The tiny plugs just sat there looking like green dots on bare soil while weeds tried to take over every open inch between them. It took a full two growing seasons before the plants knit together into anything close to a solid carpet.
That slow fill-in rate ties straight to how mondo grass grows. It spreads through underground stems called stolons at a medium pace, which means each plant only reaches a few inches outward per year. You need to space plugs 3-4 inches apart to get coverage within two years, and that close spacing drives up your cost fast. A single flat of mondo grass covers a fraction of what a bag of turf seed handles for the same price.
Foot traffic is another real concern. Arkansas Extension says mondo grass can't handle heavy walking or regular path use. The leaves flatten and the crowns bruise when people or pets cross them too often. I fixed this in my own yard by laying stepping stones through the planting. That single change kept foot traffic off the grass and gave the area a much cleaner look.
Slow Establishment Period
- Timeline: Takes 2-3 years to form a dense mat, leaving bare soil exposed to weeds during the entire fill-in period.
- Weed pressure: Open gaps between new plugs invite weed seeds, so you must hand-weed or mulch the area during establishment.
- Fix: Plant plugs at 2-3 inch spacing instead of the standard 4-6 inches to cut fill-in time and block weeds faster.
Higher Upfront Cost
- Price range: Expect to pay $1-3 per plug depending on variety, which adds up fast when you need dozens per square foot.
- Comparison: Traditional turf grass seed costs a fraction of what mondo grass plugs run for the same coverage area.
- Fix: Divide existing plants in spring to produce free plugs, or buy in bulk from wholesale nurseries to cut per-unit cost.
Foot Traffic Damage
- Sensitivity: Leaves crush and crowns bruise under repeated foot traffic, creating thin or bare patches over time.
- Arkansas Extension data: Mondo grass is not recommended for areas where people or pets walk on a regular basis.
- Fix: Install stepping stones or a defined path through planting areas to route traffic away from the grass.
Pest and Disease Issues
- Fungal risk: Anthracnose and root rot can hit plantings in poorly drained soil or areas with stagnant air flow.
- Insects: Slugs and scale insects target mondo grass foliage, leaving behind ragged edges and sticky residue on leaves.
- Fix: Ensure good drainage at planting time and apply 2% horticultural oil to control scale outbreaks when spotted.
One of the less obvious mondo grass problems shows up in colder climates. Standard mondo grass grows best in USDA zones 7-11 and can suffer winter dieback in zone 6 without a thick layer of mulch for insulation. If you live in a borderline zone, test a small patch through one winter before committing to a full planting.
When you weigh all the mondo grass cons together, the plant still works well in the right spot. Shade, slopes, and areas where you don't need a walkable surface are ideal. Plant plugs close together, add stepping stones where people walk, and give it two full years to fill in. The patience pays off with a dense, low-maintenance groundcover that only needs mowing once a year at most. Just go in with honest expectations and you won't feel frustrated by the wait.
Read the full article: Mondo Grass Care and Growing Guide
