Snowdrops are some of the earliest bulbs, and flowers in general, to bloom in spring. Galanthus nivalis is the most common species, and its cultivars are the most commonly grown snowdrops on the market. They are reliably hardy and perennial. They grow to 4 inches tall and wide and flower in mid- to late winter, long before most other plants. They are the first sign of spring around the corner. Flowers are nodding and white.