They were like moths to a flame or, more accurately, butterflies to a native plant. No sooner had I unloaded two joe-pye weed perennials from my car last August than three tiger swallowtails dive-bombed the pots, as if to validate my purchase. If only my fellow shoppers knew what they were missing...

As my beloved seedlings languished untouched on the display table, I improved my sales pitch: “Would you like a late-flowering thoroughwort to help migrating butterflies refuel? What about an aster that’s the only pollen source for some bee species?” But unlike the animals who would devour these...

Decaying logs and miniature bogs, hollowed stalks and piled rocks, nutritious pollen and leaves fallen: They’re not the stuff of traditional nursery rhymes and baby showers. But if wild mothers-to-be had gift registries, these natural supplies would top the list. Though the basic elements for...