Mexican Feather Grass (Nassella tenuissima or Stipa tenuissima) is a popular ornamental grass valued for its fine texture and graceful movement. Despite its delicate appearance, this perennial is generally low-maintenance and drought-tolerant. However, many gardeners encounter a common issue where their Mexican Feather Grass clumps begin to fall over or flop, losing their upright form. This article explores why this occurs and provides solutions to restore and maintain its elegant structure.
Common Reasons Mexican Feather Grass Falls Over
Environmental conditions influence the structural integrity of Mexican Feather Grass. Strong winds, particularly sustained gusts, can push the slender blades down. Similarly, heavy rainfall or accumulated snow can weigh down the delicate foliage, causing the clump to splay outwards. These natural occurrences are difficult to prevent.
Improper watering and nutrient imbalances contribute to flopping. Overwatering can lead to shallow root development, as it doesn’t need to seek deep moisture, resulting in a less stable base. Consistently soggy soil also deprives roots of oxygen, weakening its foundation. An excess of nitrogen fertilizer promotes rapid, lush top growth that lacks the necessary structural strength to remain upright, making it leggy and prone to flopping.
Plant age and health play a role in its tendency to flop. As Mexican Feather Grass matures, the central portion of the clump can sometimes die out, creating a hollow or “doughnut” shape. This dead center provides less support, leaving outer sections susceptible to collapse. The general vigor of the plant, influenced by factors like light exposure and disease, also impacts its upright posture.
Solutions for Reviving Fallen Grass
Strategic pruning is an effective method to rejuvenate fallen Mexican Feather Grass. Cut the entire plant back to approximately 3 to 6 inches from the ground. Ideally, do this in late winter or early spring before new growth begins, stimulating fresh, vigorous, upright blades. Regular pruning removes old, weak growth, promoting a denser and more resilient form.
Addressing soil and hydration issues is important for stability. For waterlogged areas, improving drainage involves incorporating organic matter like compost or considering a raised bed. Proper watering techniques include deep, infrequent irrigation, allowing the top few inches of soil to dry between waterings to encourage a robust root system. Avoid excessive fertilization, as this grass thrives in leaner conditions.
Dividing mature clumps revives overgrown or flopping plants. Perform this every three to five years in early spring or fall when the plant is not actively growing. Dig up the clump, inspect, and remove any dead central sections. Split the clump into smaller, healthier divisions and replant for new, vigorous growth.
Preventing Future Collapse
Selecting the correct planting location prevents future collapse. Mexican Feather Grass thrives in full sun, requiring at least six hours of direct sunlight daily for strong, compact growth. Planting in well-draining soil is equally important, as it prevents water from pooling around the roots. These conditions mimic the plant’s native arid and semi-arid environments.
Consistent, appropriate watering from the outset contributes to long-term stability. Young plants may require more regular moisture to establish, but avoid overwatering to encourage deeper roots. Once established, Mexican Feather Grass is highly drought-tolerant and benefits from infrequent, deep watering.
Minimal to no fertilization is recommended for this grass type, as it is adapted to nutrient-poor soils. Applying too much fertilizer, especially those high in nitrogen, can lead to rapid, weak growth prone to flopping. Instead, focus on improving soil structure with organic matter to support root health. Regular annual cutbacks in late winter or early spring serve as routine maintenance, promoting fresh, strong growth.