All spring-blooming bulbs, such as tulips, bearded irises, and true hyacinths, need a period of cold weather (called vernalization) in order to bloom. They need to be planted in fall, even though they won’t start to grow until temperatures warm up again.
This is one of my favorite ways to fill in bare spots in the garden where I want to bring in some color with little effort and low maintenance—no need to start seeds indoors or transplant seedlings. Just toss a few handfuls of seeds over the soil!
Pansies (and their smaller cousins, violas) are short-lived perennials that thrive in cooler weather but benefit from the warmer soil in fall. They’re very cold-hardy, with some varieties surviving down to zone 3 (especially if there’s snow cover to help insulate the roots).
Depending on your climate, perennials may go dormant in winter or even die back completely. But as long as they’re well mulched and given enough water before the ground freezes, they’ll re-emerge in spring.
Planting in autumn, when the days are cooler and shorter, helps your trees and shrubs focus on growing strong roots, rather than growing new leaves.