Pink Muhly Grass (Muhlenbergia capillaris) is a popular ornamental grass valued for its delicate, cloud-like pink plumes that appear in the fall. Like many perennial grasses, it enters a dormant phase over winter. Seasonal maintenance, specifically cutting back the dead foliage, encourages healthy new growth and prevents the plant from becoming choked with old material. Proper timing ensures the plant’s health and successful spring resurgence.
The Best Time to Cut Back
The ideal window for pruning Pink Muhly Grass is in late winter or very early spring, typically between late February and the end of March. This timing balances waiting for the coldest part of the season to pass and acting before the plant breaks dormancy. The goal is to remove the dead, brown foliage just before the new, bright green shoots emerge from the central crown.
Cutting the grass too early, such as in the fall or mid-winter, can expose the vulnerable crown to harsh cold, potentially damaging the plant. Waiting too long until significant new growth is visible results in cutting off the tips of the new foliage, creating an unattractive, blunt-cut appearance. The best cue is checking for the first signs of green growth near the base of the clump, which signals the final opportunity to prune. This timing ensures the grass puts its energy into developing fresh, vibrant blades.
The Importance of Winter Structure
Delaying pruning until late winter is based on the protective role the dormant foliage plays. The dead blades and flower stalks form a natural blanket over the crown, where new growth originates. This layer acts as insulation, shielding the plant’s core from cold temperatures and winds.
This protective layer is especially important for preventing a condition known as frost heave. Frost heave occurs when repeated freezing and thawing cycles in the soil physically push the plant’s crown out of the ground, exposing its roots to damaging cold and drying air. Leaving the spent foliage in place helps stabilize the soil temperature immediately around the plant’s base, which significantly reduces the risk of this damage. The tall, wispy structure also offers aesthetic value, providing texture and movement in an otherwise barren winter landscape.
Technique for Pruning Pink Muhly Grass
The physical act of cutting back the grass is straightforward and promotes a dense, uniform clump. Before cutting, gather the mass of foliage together, often by tying it tightly with twine or a bungee cord. This simplifies the process and makes cleanup easier, especially for larger, established clumps.
The necessary cutting tools include sharp bypass shears, hedge trimmers, or electric shears. The cutting height should be approximately 4 to 6 inches above the ground level. Cutting the grass too low risks damaging the crown. Cutting too high leaves excessive old, dead material that can stifle new growth and lead to a less vigorous plant. After the cut, remove all debris from the area surrounding the crown to ensure sunlight and air reach the base for disease prevention and healthy spring growth.