Common Buckeye Butterflies, Junonia coenia, have been flying all over the garden. I see them sun bathing where they can, couples are chasing one another intending to mate, and others were setting down among the Skippers and the Bees on the New England Asters.
Their population explosion is normal for New Jersey over the summer and autumn, however neither the caterpillar nor the adult butterfly can withstand a frost. Every year they recolonize the northern part of their range.
They're likely interested in all the Plantain which is a very common weed in my yard. I also have a small patch of penstemon and in the past have grown snapdragons, both of which are also host plants. Though it's hard to justify growing host plants this far north for a butterfly that isn't hardy.