No they're early flowering perrenial plants, usually the first non bulb plants you see in spring, I've seen them come through snow & frost, the hybrids can be a bit more tender sometimes, but they're pretty rugged none the less. They'll disappear through the summer & reappear next year, so when they've finished flowering either transplant them into a bed or keep them in the tubs & plant the tubs up with summer bulbs & add a few snowdrops & miniature crocuses for some spring variety.