Crocus — 14 species

Crocus is a corm-forming genus in the Iridaceae family, spanning roughly 90 species of late-winter and spring bloomers — from the familiar spring crocus (C. vernus) to the delicate Sieber's and Tommies types. They perform best in full sun with at least six hours of direct light, planted in sharply drained, gritty soil; the corms rot quickly in waterlogged ground and need only modest moisture during active growth. All Crocus are toxic to cats and dogs: spring species cause gastrointestinal upset, while autumn-blooming types (containing colchicine) pose a severe risk of multi-organ failure and should be treated as a veterinary emergency.