Muhly grass offers year-round interest, as its foliage and plumes remain upright and colorful through fall and into winter. However, persistent grass blades do stop growing and become brown during winter or after cold spells. For this reason, it is most ideal to cut muhly grass back in spring before new growth emerges. Larger Muhlenbergia species like the bamboo muhly may benefit from the occasional, year-round removal of canes that will leave the bulk of stems standing at a given time while also stimulating new growth.
When trimming muhly grass in late winter, cut it back to within a few inches of the ground. The grass can be cut using pruning shears or scissors, electric hedge shears or a weed eater with a suitable blade. To clean up muhly grass throughout the remainder of the season, use gloved hands or a rake to comb through the grass clump and remove loose brown blades.
Muhly is a clumping grass and can be divided to produce new clumps or restore vigor every three to four years. If ornamental grasses are not divided regularly, they may become thin or die in the center of the clump. Dig up muhly in early spring shortly before growth begins. Tear, saw or use a shovel to separate the root clump. Replant the vigorous grass from the outer edges of the clump. Perform the division and replanting promptly so that the roots never dry out.
Although muhly grass has few maintenance requirements, it will benefit from certain care practices. Muhly grass prefers full sun conditions and well-drained soils. Excessive fertilizer can harm the grass but light applications in early spring when the muhly is cut back and in midsummer will encourage vigor. Apply mulch around the plant to improve soil fertility and protect the root mass.