Fall-colored leaves of cotoneaster plant

© Steve Terrill/Danita Delimont

Fall-colored leaves of cotoneaster plant

It’s the season for pumpkins, apples, and fall colors–as demonstrated by this cotoneaster plant, a garden shrub. We have science to thank for the influx of red, orange, and yellow colors in autumn. Leaves change color as the result of a chemical process, primarily the breakdown of the green chlorophyll that allows them to absorb energy from light. As the temperature drops and days get shorter, plants’ food-making processes slow down. Orange and yellow pigments–normally masked by chlorophyll–are dramatically revealed. Still other chemical processes produce those gorgeous red and purple hues. The colors are fleeting, and soon it will be time to rake.