Mondo grass (Ophiopogon japonicus) is a popular, low-maintenance evergreen perennial often used as a groundcover or border plant. Known for its grass-like foliage, it forms dense tufts that slowly spread over time. While generally hardy and resilient, understanding its specific needs, including potential fertilization, can help it thrive and maintain its lush appearance.
Understanding Mondo Grass Nutrient Needs
Mondo grass is not a heavy feeder and can often flourish without extensive fertilization, particularly when planted in healthy, organically rich soil. It prefers a slightly acidic to neutral soil pH, typically ranging between 5.0 and 6.5. Testing your soil’s pH can help determine if adjustments are necessary to optimize nutrient availability.
Plants require primary nutrients: nitrogen (N) for lush foliage growth, phosphorus (P) for root development and flowering, and potassium (K) for overall plant health and resilience. For mondo grass, fertilization is usually only required if growth appears stunted, leaves show discoloration such as yellowing, or if the existing soil is poor in nutrients. Yellowing leaves, specifically, often indicate a nitrogen deficiency or an imbalance in soil pH.
Selecting the Best Fertilizer
For mondo grass, a balanced granular formula like 10-10-10 or 14-14-14 is generally suitable. A formula slightly higher in nitrogen, such as 12-4-8, can promote greener foliage if needed. Slow-release fertilizers are beneficial as they deliver nutrients gradually, reducing the risk of burning and ensuring consistent feeding.
Organic options, such as compost or well-rotted manure, provide gentle nutrients and improve soil structure. These can be top-dressed around the plants. Avoid high-nitrogen lawn fertilizers, as they can promote excessive leafy growth and potentially lead to fertilizer burn.
Fertilization Timing and Application
The best time to fertilize mondo grass is in early spring as new growth emerges. A single application is usually sufficient for the entire growing season. A second, lighter application can be made in mid-summer or early fall if additional vigor is desired, but avoid late summer or fall fertilization as new growth can be vulnerable to winter damage.
When applying granular fertilizer, lightly sprinkle it around the base of the plants, avoiding direct contact with foliage. Immediately after application, water the area thoroughly. This helps dissolve granules, allowing nutrients to penetrate the soil and reach roots, while preventing potential burning.
Post-Fertilization Care and Common Issues
Consistent watering is important after fertilizing, especially during dry periods, to facilitate nutrient uptake and prevent fertilizer burn. While mondo grass is somewhat drought-tolerant once established, it benefits from regular moisture without being waterlogged. Overwatering can lead to root rot, which appears as mushy, dark roots and can cause leaf yellowing or wilting.
Signs of over-fertilization include brown leaf tips, stunted growth, or a white crust on the soil surface. If over-fertilization occurs, thoroughly flush the area with water to help leach excess nutrients from the soil. Regular weeding around mondo grass helps minimize competition for available soil nutrients.