Iowa Fall Color Report: When Will The Trees Peak This Year?

Many people think that cold weather is solely responsible for the color change in leaves, but not so. Leaves begin to turn before we have any frosts. Change in coloring is the result of chemical processes, which take place in the tree as the seasons change.

During the spring and summer, a food-making process takes place in the leaves, within cells containing the pigment chlorophyll. This gives the leaf its green color. The chlorophyll absorbs energy from sunlight, and uses it in transforming carbon dioxide and water to carbohydrates, such as sugars and starch.

In the fall, the decrease in intensity and duration of sunlight, and the cooler temperatures, cause the leaves to stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellowish colors or other pigments already in the leaf become visible. 

Autumn weather conditions favoring the most brilliant colors are warm sunny days and cool, but not freezing, nights. A few hard frosts can cause the leaves to wither and fall from the tree without changing color. The degree of color may also vary from tree to tree. Leaves directly exposed to the sun may turn red, while those on the shady side may be yellow. When warm, cloudy and rainy weather dominates the fall season, leaves tend to have less coloration.

So how are the fall colors shaping up in Iowa? Here is the latest fall color report from the Iowa Department of Natural Resources:

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Northeast Iowa Fall Color Report:

The Fall color season is progressing nicely. Cottonwood, hackberry, elm, basswood and walnut are turning yellow. Virginia creeper and sumac are turning red and orange. The hillsides have splashes of color mostly from sugar maples. Fall colors appear more vibrant this year possibly due to the recent crisp, fall-like weather.  Estimated peak viewing: October 8 – 15.

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North-Central and Northwest Iowa Fall Color Report:

Yellows and oranges mixed with green dot the landscape. Ash, cottonwood, walnut, and honey locust are showing more yellows. Cottonwoods are vibrant.  Silver maples are just starting to lighten in color. Amur maples, sumac, and Virginia creeper vines are fully red. Dogwoods are showing some purple or red. Estimated peak viewing: October 8 – 15.

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Central Iowa Fall Color Report:

Ash, walnut, cottonwood, and bur oaks are all yellow.  Roadside sumac are bright red along with virginia creeper vines. More maples are turning red and yellow now. Poison ivy has turned all shades of yellow, orange, and red. Major river valleys like the Des Moines, Boone, and Iowa rivers are at 20-25% color change.  The weather this past 10 days has been excellent for promoting good colors. Estimated peak viewing: October 15 – 23.

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Southeast Iowa Fall Color Report:

Most of the landscape is still green. Elm, walnut, ash and cottonwood are starting to show a tinge of yellow. White ash and dogwood are showing a little bit of purple. Some urban maples are just starting to show a little red and orange. Estimated peak viewing: October 20.

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South-Central Iowa Fall Color Report:

Much of the landscape is still green. Drought stress is evident across the area. Sumacs, Virginia creeper and ivy vines are bright red. Early changing walnuts are nearly done. A few swamp white oaks are starting to show yellow. Maples are just starting to change to burgundy and oranges. Estimated peak viewing: 3rd week of October.

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West-Central and Southwest Iowa Fall Color Report:

Expect to see some yellow and some reds this week. Most shrubs will be at peak color, which provide most of our reds. Ash, cottonwood and walnuts are changing or will change very soon with lots of yellow. Fall prairie flowers are still showy this week to bring vivid colors to your prairie hikes. Estimated peak viewing: 3rd week of October.

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