Ornamental grasses are typically low maintenance, but most species will benefit from occasional trimming to keep a tidy appearance and remove any damaged foliage. Trimming spent flowers, seed spikes and broken stems throughout the growing season will keep the grass healthy and neat. Trimming to control the shape or size of the grass mound should be done once a year or less frequently.
Maintenance-prune your ornamental grass throughout the growing season as needed to remove dying stalks, spent blooms and seed heads. Keep your secateurs handy when watering and remove any problem foliage whenever you come across it. Cutting the stalk down to the crown of the plant will encourage regrowth and maintain the natural fountain form of the grass.
Trim your ornamental grass to control the size of the clump and improve or restore a natural shape once a year or less frequently as needed. Plan major trimming or pruning sessions for the mild climate of the fall or in the very early spring before new growth begins to appear from the crown. Cut back any branches down to the ground at the crown of the clump. Alternatively, place cuts part way down along the grass stalk or blade to give a look that is pleasing to your eye.
Water your ornamental grass deeply after trimming or pruning to reduce stress on the plant and support the roots to produce fresh foliage. Always water ornamental grasses around the base of the plant or clump instead of overhead to prevent damage to the plant and a consistently wet crown which can invite disease.