This is a blue Allium whereas all the others are purple. Plant them in full sun in neutral to alkaline (limey) free draining soil and the will flower every year in June and July. They multiply into drifts of blue flowering pom poms year on year.
Plant 15cm (62) deep and 20cm (8″) apart in September to November. Flowering height 50-70cm (20-28″) tall. Add grit or sharp sand below and around the bulbs in heavy water retentive soils. Plant in the middle of a border amongst other plants to hide the leaves which always look tatty.
A great flower for your flower arrangements.