I’ve noticed some trees and shrubs, like the burning bush, have started to color as early as Labor Day weekend this year. What causes this?
Jennifer Smith, horticulture agent for the Douglas County Extension Office, says: “Although fall color is primarily influenced by day length, weather can have some effect. Sunny days and cool nights increase sugar production in leaves to intensify color. Lower temperatures also slow chlorophyll production, making red and yellow pigments in the leaves more visible. Fall coloration usually begins in September in this region.”