How to Prune Allium cernuum 'White Dwarf'?
No pruning required, other than to remove old flowered stems and foliage

Allium cernuum 'White Dwarf' · Allium cernuum 'White Dwarf'
Grow in full sun and fertile well-drained soil. Best grown in containers where garden soil is heavy clay and prone to saturation over winter. Ideal for cut flowers, fresh or dried. See allium cultivation
No pruning required, other than to remove old flowered stems and foliage