Pansies don't like extremely cold weather, but they are excellent cool season flowers. Gardeners are encouraged to cover pansies with sheets if they are expecting a cold snap. If very cold weather threatens, straw or other types of mulch should be mounded up around the plants.
Pansies are annuals, but there are cases where they can be grown as perennials because they self-seed. Though they are small and delicate-looking plants, they are quite hardy, especially when it comes to cool climates. They don't do well in hot areas and are best planted in hardiness zones 4 through 8. They prefer to grow in full sun and rich, slightly acidic soil.