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The Science Behind Autumn's Colors

Wisconsin Department of Natural Resources
Creative Commons
Iowa is home to about one billion trees according to the USDA, many of which will change colors in October.


Iowa's over one billion trees will soon break out with red, orange, yellow, or brown leaves,  depending on the species.

On this edition of ‘Horticulture Day,’ Department of Natural Resources Forester Mark Vitosh joins Talk of Iowa host Charity Nebbe to breaks down how, when mand why the colors of fall emerge.


The annual changing of the leaves is quickly approaching, according to Vitosh. Vitosh says trees usually turn around the middle of October, give or take about ten days depending on factors like weather conditions. Clear days and nights speed up the processes that lead to fall colors. 

Later on, Vitosh and Iowa State University Horticulture Extension Specialist Richard Jauron answer questions from calls and emails about a wide variety of trees and plants.


  • Mark Vitosh, Department of Natural Resources Forester
  • Richard Jauron, Iowa State University Horticulture Extension Specialist


HorticultureHort Day
Charity Nebbe is the host of IPR's Talk of Iowa
Katelyn Harrop is a producer for IPR's River to River and Talk of Iowa