How to Prune blue-eyed grass 'E.K. Balls'?
No pruning required

blue-eyed grass 'E.K. Balls' · Sisyrinchium 'E.K. Balls'
Grow in poor to moderately fertile, well-drained, neutral to slightly alkaline soil in full sun; plants are drought tolerant once established. Protect from excessive winter wet. Suitable for an alpine trough or gravel garden. May have the potential to become a nuisance as seeds prolifically
No pruning required