Although some butterfly species, such as the monarch, migrate to warmer climates before winter arrives, most pollinators prefer to stay put and seek shelter from the cold. Many bees hibernate under brush piles, leaf litter and other garden debris, while others will nest in the ground, often near the garden beds where they feed. To give pollinators the winter shelter they need to survive, hold off until spring to clean up your garden rather than removing all debris and cutting back perennials to the ground in the fall. Some bees don’t emerge from hibernation until late May, according to the Xerces Society, so the longer you can wait the better.