Dwarf Mondo Grass, scientifically known as Ophiopogon japonicus ‘Nana’, is a highly sought-after, low-growing evergreen perennial that serves as an excellent lawn substitute. This plant is valued for its fine texture, dark green, grass-like foliage, and the minimal maintenance it requires once fully established. This cultivar forms dense, arching tufts that create a uniform, carpet-like effect, typically reaching only four to six inches in height. Successful establishment and uniform coverage depend on precise initial planting decisions, particularly the distance between each plant.
Preparing the Planting Site
Preparing the ground is a necessary step that ensures the long-term success of the groundcover. Dwarf Mondo Grass thrives best in well-drained soil, which helps prevent root rot. The preferred soil acidity should be slightly acidic to neutral, ideally ranging between a pH of 5.5 and 6.5. Testing the soil pH is a good practice, and if the soil is too alkaline, incorporating organic matter like compost can help to lower the pH. The planting area must be cleared of all perennial weeds, as competition for water and nutrients will significantly inhibit the spread of the slow-growing Dwarf Mondo Grass. Thoroughly mixing in a layer of compost or other organic material will improve the soil structure, enhancing both drainage and nutrient content.
Optimal Spacing for Dwarf Mondo Grass
The distance between planting points is the single greatest factor determining how quickly a space will achieve a dense, seamless green carpet. Dwarf Mondo Grass spreads slowly by producing short, underground stems called stolons, which are responsible for the plant’s gradual lateral expansion. Closer spacing dramatically reduces the time required for these stolons to connect and fill in the intervening gaps.
For the fastest possible coverage, aiming for a dense mat in one to two years, plant the individual plugs or divisions only two to four inches apart on center. A standard rate of coverage, achieving a full carpet in approximately three years, can be accomplished by spacing the plants four to six inches apart. If budget is a primary concern and a longer establishment time of four or more years is acceptable, the plants can be spaced six to eight inches apart.
Step-by-Step Planting Technique
The physical process of planting begins with the separation of the plant material, which often arrives as plugs in a tray or larger clumps. If planting from trays, gently tease apart the root mass to separate the individual grass pieces, ensuring each division retains a healthy section of roots. For larger clumps, a sharp knife or garden fork can be used to divide the mass into smaller tufts, each containing a few leaves and a viable root system.
The planting hole should be dug only slightly larger than the root ball or division you are placing into it. It is important to avoid planting the material too deep, as the crown, the point where the leaves meet the roots, must remain precisely at the soil surface level. Place the root mass into the prepared hole and backfill with soil, lightly firming the surrounding area to remove any large air pockets.
Ensuring Establishment and Spread
Immediately after planting, provide a thorough watering to settle the soil around the newly placed root systems. Consistency is crucial during the initial establishment phase, requiring the soil to be kept moderately moist for the first six to eight weeks. Care must be taken to avoid overwatering, as Dwarf Mondo Grass is susceptible to root rot if the soil becomes soggy or waterlogged for extended periods.
Once established, the plants become relatively drought-tolerant, though they perform better with occasional watering during dry spells. Fertilization needs are minimal. A light application of a balanced, slow-release granular fertilizer in the early spring can promote vigorous growth and runner production. Alternatively, an annual top-dressing of compost provides a slow feed of nutrients while also helping to retain soil moisture, encouraging spread via underground stolons.