The decreasing intensity of sunlight in the Fall causes production of chlorophyll to decrease, giving other pigments a chance to "shine."
When the Green Goes Away a Leaf Shows Its Other Colors
Amanda McNulty is a Clemson University Extension Horticulture agent and the host of South Carolina ETV’s Making It Grow! gardening program. She studied horticulture at Clemson University as a non-traditional student. “I’m so fortunate that my early attempts at getting a degree got side tracked as I’m a lot better at getting dirty in the garden than practicing diplomacy!” McNulty also studied at South Carolina State University and earned a graduate degree in teaching there.