Allium Sphaerocephalon

Allium bulbs are usually planted from early to mid-autumn for flowers in late spring and early summer. If you are looking for allium bulbs for planting now in the UK, plant them as soon as conditions are suitable and avoid storing them for long periods. Choose a sunny, sheltered position with free-draining soil, as alliums do not cope well with winter wet. Planting at the right time gives the bulbs time to establish roots before the ground becomes cold.

The most common reason allium bulbs fail is excess moisture around the bulb. Heavy, waterlogged soil can cause bulbs to rot before they establish. Planting too shallowly, choosing a shaded spot or damaging the bulb before planting can also affect growth. For the best results, plant allium bulbs deeply in a sunny position with good drainage. Alliums are naturally drought tolerant once established, so they are far better suited to a dry, sunny border than a damp or exposed area of the garden.

Allium bulb size varies naturally, so some bulbs may be smaller than expected depending on their type. A dry, papery outer skin is also normal, provided the bulb underneath is firm and solid. As ornamental alliums are closely related to onions and garlic, they can have a light onion-like smell. This is not usually a problem. Do not plant bulbs that are soft, wet, badly mouldy or have a strong sour or rotten smell, as these are signs that the bulb may have started to decay.

Allium bulbs should flower in the colour and form described on the product page. Flower photographs show the expected result, but natural blooms can vary slightly in shade depending on sunlight, weather and growing conditions. Images can also appear brighter or darker across different phone and computer screens. A sunny position and healthy, well-established bulb will give the best chance of strong stems, full flower heads and the clearest colour. Alliums flower mainly in spring and early summer, with many producing attractive seedheads afterwards.

Many allium bulbs are perennial and can return for several years when planted in a suitable position. After flowering, leave the foliage until it has yellowed and died back naturally, allowing the bulb to store energy for the following season. Their dried seedheads can also be left in place for added structure in the garden. Free-draining soil is especially important for repeat flowering, as bulbs are more likely to weaken or rot in damp ground.