When you hear the words “trees” and “autumn,” you think brilliant red, orange and yellow leaves. But those in the know think bargain. Many nurseries slash prices in October because most trees and shrubs can’t survive the winter frost unplanted. And in many areas, this is the best time to plant (roots establish faster when there are no leaves to feed). Come spring, you’ll enjoy the fruits (and shade) of your labor while everyone else is paying full price.