May
Some people see the withering foliage of spring bulbs as eyesores. But you’re better off waiting a few weeks before you whip out your pruning shears. For now, just remove the fading flowers. The withering leaves are still absorbing energy from the sun to feed the bulbs beneath the soil. If you remove the leaves straightaway, you greatly reduce the chances of the bulbs flowering again next year so wait until they have totally dried out before removing.
* Adjust months slightly according to your climate zone.