Blooming from late spring to early summer, it’s important to know when to plant allium bulbs to get the most out of these beautiful flowers in the garden. As you are best planting allium bulbs in the ground in autumn, it is the same principle for planting allium bulbs in pots. When to plant allium bulbs in potsIf you’ve landed on this page, then you are no doubt wondering ‘when to plant alliums in pots’. ‘Once you’ve planted your allium bulbs in pots, keep them in a cool, sheltered spot outside,' says Chris. So don't hesitate, planting allium bulbs in pots now will ensure a gorgeous blooming garden in 2026.