What makes those leaves change?
Taking a trip to the Morton Arboretum's Fall Color Festival may be a feast for your eyes, but do you really know when each leaf is changing color and why?
Ed Hedborn, manager of plant records at the Morton Arboretum, explained that how fall color expresses itself depends completely on the weather.
"If we have bright, sunny, warm days and cool, but not cold, nights and the plants have adequate moisture, that's when you get the brightest and the most color," he said. "If you get cloudy days and cold nights the colors may be more muted."
Special events manager Marilyn Baysek understands this, and knows that foreseeing what leaves will look like at a particular time in the month is a difficult task.
"We can't really predict when we're going to get the peak fall color or the best fall color," she said. "It changes daily. It's a progression. At any point during the month of October different trees turn colors at different times."
Because of this, the Fall Color Festival is spread out over a four-week period so everyone can enjoy different colors, no matter which day they come.
But for Arboretum enthusiasts, Hedborn has a general idea of some trees and plants to look out for each week of the month:
• As September becomes October, Sumacs and Virginia creeper become a vibrant red.
• In early October, Green and White Ash, Burr Oak and Kentucky Coffeetrees turn yellow.
• At the end of the first week, Hickories and American Elms warm up with a golden yellow color.
• Late in the second week, Sugar maples change to a variety of colors. "The color a sugar maple changes (to) depends on the year," Hedborn said. "It has the ability to change yellow to orange to red depending on weather conditions for a particular year."
• In late October, White Oaks turn to an almost-purple color.
• At the beginning of November, some of the last trees make their transitions, including Callery Pears from East Asia with leaves becoming a salmon shade.
Hedborn added that the trees aren't the only plants transforming in the fall.
"People don't think of a prairie as being colorful in the fall, but it is," he said. "The grasses go from green to yellows to rustic colors to almost purple."
He added that a lot of late season composites like sunflowers and goldenrods will be blooming in October too.
Baysek said that because the Arboretum looks different every day, there are often visitors who come more than once in October.
"We have people who come early in the month, then they come later in the month, or some of the people drive through on a weekly basis just to watch the progression (of color change) because it is intriguing," she said.
Visitors can call the arboretum's color hotline at (630) 719-7955 to see what trees are changing before attending the festival. The list is updated weekly.