The main downsides of dwarf grass are high cost, slow fill-in time, and heavy weed pressure during the first year or two. This question most often refers to dwarf mondo grass types like Nana and Gyoko-ryu that stay under 4 inches tall in your yard.
I planted 100 Nana plugs between my front walkway stones two springs ago. The first year was rough. Weeds popped up faster than the tiny mondo plants could spread, and I spent hours on my hands and knees pulling every invader by hand. The dwarf plugs just sat there looking small while crabgrass tried to swallow them whole. That first season tested my patience more than any other garden project I've taken on.
The science behind these dwarf mondo grass problems explains why they're so slow. Dwarf varieties have smaller leaves with less surface area to catch sunlight. Less light energy means fewer stolons pushing outward each season. Standard mondo grass might spread 3-4 inches per year, but dwarf types manage just 1-2 inches in the same time frame. That slower spread leaves bare ground exposed to weeds for much longer.
Cost hits your wallet hard with dwarf varieties. You need plugs spaced at 2-4 inches apart to get full coverage in a decent time frame. Standard mondo grass can go 4-6 inches apart and still fill in. That tighter spacing means you buy roughly twice as many plants per square foot with dwarf types. At $1-3 per plug, a 50 square foot planting area can run you $200 or more before you even buy soil or mulch.
Slow Growth and Fill-In
- Timeline: Full coverage takes 2-3 years with proper spacing, leaving bare soil exposed during the whole wait.
- Root cause: Smaller leaf area produces less energy for stolon growth, so each plug expands just 1-2 inches per year.
- Your fix: Plant at 2-inch spacing and mulch between plugs to hold back weeds while your dwarf grass gets going.
Higher Plant Costs
- The math: Dwarf types need 4-9 plugs per square foot at 2-4 inch spacing versus 1-4 for standard types.
- Price impact: A small 50 square foot area can cost $200-450 in plugs alone with dwarf mondo grass.
- Your fix: Divide your existing plants each spring to produce free plugs, or buy in bulk online to cut your per-plug cost.
Weed Invasion During Setup
- The risk: Small, slow plugs can't compete with fast-growing weeds that fill every gap between your new plants.
- First year reality: You'll spend hours hand-weeding until your dwarf grass forms a dense enough mat to block weeds on its own.
- Your fix: Pre-treat the planting area with weed control 4-6 weeks before you install your plugs to give them a clean start.
These dwarf groundcover disadvantages are real, but the trade-off comes down to your patience and budget. Dwarf mondo grass creates a stunning low carpet that no standard variety can match. But you pay more upfront, wait longer for results, and work harder to keep weeds out during those first two years.
Here's my best advice for making dwarf grass work in your yard. Spray or smother weeds in your planting area at least a month before you put plugs in the ground. Spread 1 inch of fine mulch between your new plants to block weed seeds from getting light. Water your plugs deep twice a week for the first summer to push strong root growth. Set your expectations for a two to three year timeline and check your beds for weeds every week during year one. The end result is worth the effort, but only if you go in knowing what the first couple of years will ask of you.
Read the full article: Mondo Grass Care and Growing Guide
