A humane backyard is a safe haven for wildlife—a space where animals can thrive free from pesticides, trapping and other threats.

By some human standards, my pond is a hot mess. Underneath and around the water lilies are fallen leaves, branches and other debris of decomposing plants. Along the edges, sea oats, sedges and swamp sunflowers hug the rocks. But if humans are picky in their desire for orderliness, frogs are just as...