What is it like to live at the border of time zones? Where “six o’clock” means something different where you live than it does ten minutes away?
As someone who lives pretty solidly in Central Time (US), I haven’t had to reckon with that, and it comes to mind because of something more personally relevant – USDA hardiness zones.
For the unitiated, USDA hardiness zones are a map of average coldest temperatures across the United States, which are grouped into zones to indicate which plants your winters (probably) won’t kill. A zone 7 minimum, like some pomegranates, won’t handle the negatives Fahrenheit well. This makes them viable in Portland, Oregon – likely because of the Pacific – but not so much in northern Illinois. Which makes sense! The finer problem is this: because of Lake Michigan, much like with the Pacific, the Chicago suburbs closer to the lake are a zone warmer than the ones further away. We cross this divide regularly. The Morton Arboretum, which I’ve written about before, might actually straddle it. So if a fig tree’s minimum zone is 6… can it survive one or two suburbs over?
The answer, realistically, is it depends on the specific conditions where you specifically plant it, and the zones are more guideline than rule. But it is an interesting thought experiment, is it not? Because at some point, “just another suburb over”… is one too many. Which is why northern Illinois can’t grow pomegranates.
I live in Chicago right next to Lake Michigan. In the spring, it’s significantly cooler here because the lake is still cold, so lilacs blossom later than the ones growing a mile inland. That means I get two lilac seasons, which is just fine.