How to prune allium 'purple sensation'

Remove seedheads after flowering in early summer if desired; let foliage die back naturally through summer. Cut spent flower stems to ground level with clean secateurs after the globe fades, or leave them for structural interest. Never cut the foliage until it is fully yellow and pulls away easily.

Once annually after flowering, or simply leave seedheads to self-naturalise. Allium 'Purple Sensation' needs very little pruning. You can deadhead spent globes if you want to prevent self-seeding, but many gardeners leave the dried seedheads as they provide ornamental interest well into summer. Allow the strap-like foliage to die back naturally so the bulb can store energy for next year.

Cut spent flower stems to ground level with clean secateurs after the globe fades, or leave them for structural interest. Never cut the foliage until it is fully yellow and pulls away easily.