How to Prune allium 'Red Eye'?
No pruning required, other than to remove old flowered stems and foliage

allium 'Red Eye' · Allium 'Red Eye'
Grow in full sun and fertile well-drained soil. It is best to grow in containers where garden soil is heavy clay and prone to saturation over winter. See allium cultivation
No pruning required, other than to remove old flowered stems and foliage