We finally had a frost, but having it so late made a few things clear. Autumn colors are definitely the result of a dance between falling light levels, frost, and overall weather. Jack Frost’s paintbrush does not operate all on its own. But the details are tricky.
For instance, the dogwoods turn reliably red early in the season, even if nothing else does, and even if it’s still warm. Also, the dogwoods are an understory tree, growing under the broad arms of the taller trees which, if there were a frost, would protect them from it. So it can’t be frost turning them red. On the other hand, as the tall trees lose leaves, the dogwoods get more light, not less. Hmmm. Well, by then they’ve already started getting red, so maybe there’s no turning back.
The wild black cherry over the deck is reliable for turning early, but the one at the edge of the lawn always turn a couple of weeks later. Despite this difference, neither requires a frost, and they share an opinion on how colorful to be in a given year. So I’m guessing it’s a combination of daylight and position in the yard for when they turn, but things like rain, drought, and summer temperatures for color intensity.
The sugar maples had wisps of color here and there as the hours of daylight fell, but they only burst into their full glory with the frost. Every year they’re different as to when they change, as well as to how bright their colors are. So the maples are taking all factors into account.
Looking around the yard, I can mostly sort all the other deciduous trees, shrubs, and groundcovers into one of those three categories: the self-motivated, the socially aware, and the introverted but ultimately exuberant. Different manners, but the happy result is to paint the glory of Michigan’s autumn over a bigger canvas than Jack Frost could manage on his own. It takes all kinds.