Allium

Large-flowered alliums are great to combine among perennials in the border. The leaves of the Allium start dying off before flowering time. This is the moment when the flower bulb starts to ripen and has almost finished growing. If the Allium is planted among perennials, you can camouflage the dying leaves among the other plants and it will be less noticeable.
Large-flowered Alliums can stay in the ground for several years. As long as the flowering remains beautiful, leave them in place. If the flowering diminishes, that's the time to dig up the bulbs after flowering. In summer, keep the bulbs warm and dry. If the bulbs are still in good condition, they can be replanted elsewhere in the garden in autumn.
Plant Allium in a sunny spot in well-drained soil.

The small-flowered Alliums are ideally suited for naturalising in a sunny spot in permeable soil. With the exception of Allium triquetrum and Allium ursinum, which also thrive in a (semi-)shaded spot.