Lily bulbs are miracles of nature. They contain a complete plant and enough food to keep it through a year of growth. Each bulb contains its own precise clock to manage growth from spring shoot to full flower.
Each variety of lily has its own bloom time, but all lilies start growing when the ground warms. Cold weather, cold soil and cloudy days may delay the start of growth.
Fall-planted bulbs and bulbs planted as soon as the ground is frost free will put up shoots within a few weeks—often before the last frost. Late-planted lilies or potted plants set out in the garden after blooming may not bloom reliably their first year in the garden.
Each class of lily blooms during a specific range of time. Most Asiatic lilies bloom from 30 to 45 days after growth begins. Orientals take from 40 to 90 days. American native tiger lilies are the latest bloomers, 100 to 120 days after spring growth starts.
Gardeners may choose several varieties from two or more classes of lily so they have lilies blooming from mid-June until mid-August. Once lilies bloom, they stop growing and simply gather food for the next year's growth.