Life … Plants Vascular Plants Monocots Agaves, Orchids, Irises, and Allies Amaryllis, Onions, and Allies Onions Caerulea Blue Ornamental Onion species 485 observations Blue Ornamental Onion Allium caeruleum Field notes Key traits Layer Herbaceous plants Light Full sun Moisture Dry Well drained Moist Soil Sand Loam Organic Drought tolerant Yes Habit Erect Plant type Bulb Perennial Poisonous From NC State Extension. Close