Why do Leaves turn Color in the Fall?

Fall is one of the most beautiful seasons as the leaves turn brilliant colors and the trees start to shed their leaves for the growing season. Have you ever wondered why leaves change color in the fall? Let’s find out!

Most of the year the leaves on trees are green because of the green pigment in chlorophyll that allows the trees to produce the energy that they need to grow, bloom and produce fruit. The other colors, except red and purple, needed for leaves to color in the fall are already but masked by the chlorophyll. The red and purple pigments are produced after the chlorophyll is destroyed. As fall progresses and certain weather conditions are met the leaves will develop an abscission layer at the base of the petiole, where the leaf attaches to the stem, which prevents sugars from being transported down the trunk to the roots for storage. As the sugars accumulate in the leaves the high concentration causes more intense colors. Certain trees, such as oaks and maples, naturally have more fall color than others and these types of trees tend to be more common in Michigan, New England and other parts of the country than Kansas. This makes it appear our native trees do not color as well however they simply have a different range of colors.

Weather does play a role in how well a tree colors in the fall. Unfortunately, with our hot and dry summer our fall color is likely to be less showy this year than others. Other weather conditions such as cloudy days and warm nights, heavy rains in the spring or fall and frosts will also impact the amount of fall color we have and how long it hangs around.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu