Lisle, Ill. (October 22, 2021) — A dry summer in the Chicago region may result in earlier fall color changes, according to The Morton Arboretum’s tree scientists.

Stress, such as not getting enough water, is among the factors that cause leaves to change from lush green to various hues of red, orange and yellow earlier than they might otherwise, according to the Arboretum’s forest ecologist, Christy Rollinson, Ph.D. “We’re seeing some species changing color and losing their leaves earlier in this season than in wetter years, but drought-resilient species like oaks should be less affected and may still provide us with a colorful show,” she said.

When will be the best time to catch the best fall color views? According to Rollinson, “It’s more a question of where to see changing colors rather than when to see them, since different species change at different times.” Places like the Arboretum, where there is a large amount of tree species diversity, will have something to see all season long, she noted. Some fall colors are already emerging throughout the Arboretum, which visitors can track in a weekly Fall Color Report on its website.

The timing of when leaves change colors, how much color they will show and when they will begin to lose their leaves depends on numerous environmental factors, such as temperature, rainfall, hours of sunlight, soil conditions, and the level of stress the tree is experiencing. While Rollinson indicated that fall color is typically at its best in mid- to late October in the Chicago area, “The peak, when leaves turn to their most vibrant colors, is more difficult to predict than the onset, so it’s best to keep looking at your neighborhood trees to time your fall color excursions.”

Fall is the best time to plant a tree

Fall is more than just a time to watch color changes, it’s also a perfect time to plant trees. According to Julie Janoski, plant clinic manager at the Arboretum, planting trees in the fall offers many advantages. “The cooler temperatures are less stressful for newly planted trees. When air temperatures are cooler than the soil, new root growth is encouraged without new top growth, helping to establish the root systems before the temperatures rise to stressful levels in the hot weather months of the following year,” she explained.

The Arboretum’s Plant Clinic recommends that homeowners and communities plant a diversity of tree species. “Take a look around your neighborhood and try to plant something different than your neighbors,” Janoski said. “This can raise the tree’s chances of survival and benefits the health of the regional forest. It can also improve a neighborhood’s fall allure.”

When properly planted and cared for, Rollinson says, trees have the greatest chance to reach maturity, enabling them to provide the greatest possible benefits to the people who live around them, including cleaner air, lower energy bills and stormwater interception, among others. They also provide habitat for other plants, insects, birds and animals.

Those with questions about tree planting and care can find information on the Arboretum’s website at mortonarb.org or through its Plant Clinic.