As I started weeding the blueberry bed in May, I was only vaguely aware of the sounds around me, including a rather noisy bird warbling from the nearby honeysuckle arbor. I’d set aside an hour to tackle a job that had been put off far too long and, intent on the task at hand, I didn’t pay much attention.

The blueberries share their bed with mint. We didn’t plant it; it was here when we bought this place. Knowing how invasive it can be, Mr. Petrol Head wanted to rip it all out. But I love...