Jumbo Elephant Ear Bulb - Colocasia esculenta 19/20 in. BIGGEST BULB AVAILABLE Height: 72-96" Hardiness Zone: 8-11 / Suitable Zone: 4-11 Planting Depth: 3-4" / Planting Spacing: 24-36" Colocasia esculenta - Planting Instructions Included. Size 19/20 in - Massive Size Bulb - HUGE!