Shoulder Season Brings Butterfly Bonanza to South Jersey Gardens

South Jersey gardens are abuzz with life in September as butterflies and caterpillars take advantage of the 'shoulder season'. This transitional period between summer and fall is a crucial time for monarchs, which are powering up for their epic migration to Mexico. The 'super generation' of monarchs, which live six to nine months, can be seen consuming nectar from late-blooming flowers like goldenrod, sedum, and asters.

These butterflies will eventually make their way to Cape May, where they'll wait for the right conditions before crossing over the Delaware Bay. Meanwhile, monarch caterpillars are busy fattening themselves on milkweed, their only source of food. Once they've reached a certain size, they'll leave the milkweed to form a chrysalis and pupate.

September is also a peak time for black swallowtail butterflies, which are not as picky about their host plants. Unlike monarch caterpillars, which can only eat milkweed, black swallowtail caterpillars enjoy a variety of plants, including parsley, dill, fennel, and Queen Anne's lace.

Black swallowtails use mimicry to help ward off predators, making them harder to spot. They also have a defense mechanism called an osmeterium, which releases a stinky chemical when threatened. If you find black swallowtail caterpillars, be sure not to disturb them and provide them with plenty of host plants.