Pink Muhly Grass (Muhlenbergia capillaris) is a popular ornamental grass valued for its distinctive late-season color. Its aesthetic appeal comes from fine-textured, deep green foliage topped in the fall by airy plumes of pink or purplish-pink. This visual effect, often described as a “pink cloud,” makes it a sought-after addition to many landscapes. The grass is appreciated for its hardiness and tolerance for heat and drought once established.
Determining Ideal Spacing
The optimal distance for planting Pink Muhly Grass depends on the desired visual effect, as the plant naturally grows in tidy, clump-forming mounds. The average mature width of a single clump is between two and three feet, which serves as the baseline for all spacing decisions.
For gardeners aiming for a seamless, continuous “pink cloud” or drift effect, closer planting is appropriate. To achieve this mass planting look, plants should be placed approximately 18 to 24 inches apart, measured from the center of one plant to the center of the next. This spacing encourages the plumes and foliage of adjacent plants to overlap slightly, creating an uninterrupted expanse of color in the fall.
If the goal is to showcase individual specimens with their full, natural dome shape, wider spacing is necessary. For an accent planting, a distance of three feet or more between plants allows each clump to mature without competition or crowding.
Site Selection and Soil Requirements
The most important environmental factor for this grass is sufficient sunlight, which directly influences the vibrancy and abundance of the fall plumes. Muhlenbergia capillaris requires a location that receives full sun, meaning at least six to eight hours of direct sunlight each day, for optimal growth and flowering. Insufficient light will result in fewer flowers and potentially cause the foliage to become weak or “floppy.”
Pink Muhly Grass is known for its adaptability and tolerance of lean, poor soil conditions, including sandy, rocky, or slightly clay-based compositions. However, the soil must have excellent drainage, as the plant will not thrive in heavy, waterlogged conditions, which can lead to root rot. If planting into dense clay, incorporating organic matter or coarse sand is necessary to improve porosity. The best time to plant is in the spring after the last frost or in the early fall.
Post-Planting Care and Pruning
Establishing the root system requires a specific watering schedule immediately following planting. New plants should be watered frequently enough to keep the soil consistently moist for the first few months, encouraging the development of deep roots. Once established, the grass becomes highly drought-tolerant and requires minimal supplemental watering. Over-watering established plants, especially in poor-draining soil, is a common error to avoid.
Annual maintenance involves a hard cutback, which promotes dense, tidy growth in the subsequent season. This pruning should be performed in late winter or early spring, before the new green shoots begin to emerge. Using sharp shears, cut the entire clump back to a height of four to six inches above the ground. Cutting back too late risks removing emerging new growth, and summer pruning interferes with the formation of the fall flower plumes.
Pink Muhly Grass prefers lean soil and generally does not require fertilization. Applying too much fertilizer can be detrimental, leading to overly lush, weak growth that causes the plant to flop over, especially when the heavy flower plumes appear. If the soil is extremely poor, a light, balanced, slow-release fertilizer can be applied in early spring, but this is usually unnecessary for healthy plants.