Plant to Lure — and Feed — Migrating Butterflies

By Margaret A. Barker

      “Obsessed with food, caterpillars are a mouth attached to a stomach.”

     Why would anyone buy a plant that a worm is going to devour?

     Because that so-called worm might be the larva of a beautiful butterfly. Female butterflies attach eggs to plants that serve as food for hatched-out larvae — caterpillars. The hungry, growing caterpillars will eat their host plant.

     As adults, butterflies require nectar plants for fuel and reproduction. While flying from flower to flower for sugary treats, they’re doing good work, too. Though not as adept as bees at pollinating plants, foraging butterflies make plenty of pollen-grain deliveries.

     All kinds of pollinators will benefit from local native plant sales this spring. The 31st Annual Bowie-Crofton Garden Club’s Spring Plant Sale (8am-noon Saturday, April 27) at the Bowie Branch Library promises plenty of easy-to-grow butterfly plants. At a 10am library talk, you’ll also learn about specific butterfly host plants such as those needed by the big butterflies that have long tails: swallowtails.

     The four swallowtail species we see around our part of the Mid-Atlantic, are, in order of abundance: tiger swallowtail (yellow with black stripes); spicebush swallowtail (mostly black); black swallowtail (mostly black); and zebra swallowtail (black and white). 

     Tiger females lay eggs on black cherry trees as well as tulip poplar trees, sweet bay magnolia and a few other plants. Spicebush caterpillars need to feast on … you guessed it: spicebush. White sassafras will do, too. 

     The black swallowtail is a bit more particular. Its caterpillar, nicknamed parsley worm, munches plants related to carrots: dill, fennel, parsley, golden Alexander, Queen Anne’s lace.

     Zebra swallowtails are even pickier. Their caterpillars eat only the small native paw paw trees. Paw paw leaves also supply chemicals that may protect zebras from predator birds.

     Some of the best butterfly nectar plants include native New World perennials like asters, cutleaf cone flower (Rudbeckie laciniata), brown-eyed Susan (Rudbekia triloba), the cup plant, Jeana phlox (a new mildew-resistant variety) and Joe Pye weed, Bowie-Crofton Garden Club member Elmer Dengler’s favorite.

     Swallowtails and monarch butterflies are lured to zinnias, too. An annual that’s native to Mexico, zinnias provide good butterfly landing pads as well as plenty of nectar. A high-nectar heirloom zinnia variety, the California Giant, can be had at the Bowie plant sale.

     Grow the right butterfly plants in all the right places with plenty of sunshine, and by hot-weather time, go out and enjoy the butterfly show.