As a rule, spring-flowering bulbs are "hardy." This means that they can survive the cold winter months after being planted in the fall. Indeed, hardy bulbs require a period of cold to activate the biochemical process needed for flowering. Many hardy bulbs can be left in the ground to flower year after year.
Most summer-flowering bulbs are "tender." Tender bulbs cannot survive harsh winter conditions and are planted in spring after the final frost. In fall, these bulbs must be dug up and stored indoors. One notable exception is the lily.
About Winter Mulch
Most people think winter mulch is like a thick sweater that spring-flowering bulbs should put on before the cold sets in to keep them from freezing. But it's really more like a scarf that should be applied once the ground is already cold. This keeps the soil temperature consistently cool over the winter, helps retain moisture and minimizes damage from frost. Mulch too early and the overly warm soil conditions can promote disease and give mice and other unwanted pests a cozy place to build their winter den.