Mondo grass (Ophiopogon japonicus), a groundcover also known as monkey grass, forms short, dense clumps of narrow leaves 8 to 12 inches long. The leaves arch gracefully, creating a fountain of green in rock gardens or along borders. Freezing temperatures damage the leaves, however, and older plants look scruffy after a cold winter, detracting from the landscape. Trim back mondo grass and remove the unsightly growth, clean up the flowerbed and ready the yard for spring.
Evaluate the grass for damage in late winter or early spring, before new growth appears; Southern Living magazine suggests trimming mondo grass in late February. Remove sticks, twigs or debris that may interfere with a mower or string trimmer.
Set the lawnmower at its highest setting and ensure it has a sharp blade. Dull blades will shred the edges of the grass. Only use a lawnmower on even ground; string trimmers are a better choice for uneven or small areas.
Run the lawnmower over the mondo grass, avoiding nearby plants. If you use a string trimmer, cut the grass 3 to 4 inches above the crown.
Rake and dispose of the clippings, cleaning around the grass and removing habitat for insects and disease.