Water thoroughly when the top 2-3 cm of soil feels dry. Allow soil to dry slightly between waterings. Reduce watering during dormancy in late summer and fall to prevent root rot.

Ensure good drainage to avoid waterlogged conditions.

Remove spent flower stalks after blooming to prevent seed formation and direct energy back into the bulb. Foliage should be left to yellow and die back naturally to feed the bulb for the next season.

Cut back dead foliage in late fall or early winter.

Divide overcrowded clumps in early autumn when the foliage has died back. Carefully separate bulbs and replant them at the recommended depth.

Alternatively, propagate from fresh seed sown in autumn, though flowering may take several years.

Repot container-grown Allium grande every 2-3 years in early autumn, or when the bulbs become crowded. Use a well-draining potting mix.

This also provides an opportunity to inspect bulbs for health and divide them if necessary.