How to Prune blue fescue?
Comb out dead foliage in spring and trim off damaged parts on older foliage

blue fescue · Festuca glauca
Also known as: grey fescue; ornamental blue fescue grass
Grow in poor to moderately fertile, well-drained soil in full sun. Clumps tend to die out in the centre. Ideally divide every three years. Further ornamental grasses cultivation advice
Comb out dead foliage in spring and trim off damaged parts on older foliage