Giddy with excitement, we sawed an old Scotch broom, exhumed its roots, and packed it lovingly out of the park. In its place, a smattering of brilliantly saturated yellow petals lay at rest on the mulch. The moment before we started, I watched those yellow blooms, delicately folding in on themselves, dance with a bumblebee in the breeze, and I felt a pang of regret for what we were about to do. To take the life from this particular plant in this particular place was good for the whole, on balance. But to disturb the soil, to take the flowers from the pollinator–these things still don’t settle easily in my…