Native Butterfly Plants

Two completely different jobs

A butterfly's life has two halves and they eat different things.

The adult drinks nectar and can take it from almost any suitable flower, including plants from other continents. The caterpillar eats leaves, and it is usually restricted to a small number of plant species, sometimes to exactly one.

Nearly every garden marketed as a butterfly garden addresses only the first half. It supplies nectar to adults that emerged somewhere else. That is worth something, and it is not the same as supporting a population.

The host plant list is short and specific

Monarch caterpillars eat milkweed and nothing else. Spicebush swallowtails eat spicebush and sassafras. Black swallowtails eat plants in the carrot family, which is why golden alexanders belongs in a butterfly garden. Karner blues eat wild lupine, full stop. Gulf fritillaries eat passionflower. Pipevine swallowtails eat pipevines.

Fritillaries eat violets, which is worth pausing on, because violets are the thing most people are spraying out of the lawn.

Skippers, which make up a large share of the butterflies in most yards, eat native grasses. Little bluestem, big bluestem, switchgrass, and sedges are butterfly plants, and they never get sold as such.

Accepting the damage is the actual commitment

If the host plants are working, they will be chewed. A milkweed stripped to the stems in August is a milkweed that did its job.

The way to make that tolerable is quantity and placement. Three milkweeds look like a problem; nine look like a planting. Put host plants where damage reads as normal, in a meadow area or the middle of a bed, and put the nectar plants where you want things to look composed.

And do not spray. Anything that kills caterpillars kills these caterpillars, including products marketed as organic or biological. Bt is lethal to butterfly larvae. Mosquito fogging services treat the vegetation caterpillars live on.

What makes good nectar

Adults need somewhere to stand, so flat-topped flowers and broad daisies work better than nodding tubes. Stiff goldenrod, Joe-Pye weed, blazing star, coneflower, and mountain mint are heavily used for exactly that reason.

Extend the season at both ends. Early butterflies emerging in April need something open, which is what creeping phlox and woodland phlox provide. Fall migrants need late nectar, which is what asters and goldenrods provide.

A shallow depression of damp sand or mud, sometimes called a puddling station, gives males a source of the minerals they need. It costs nothing and gets used.

Sources: Xerces Society for Invertebrate Conservation (butterfly conservation and host plant lists); US Fish and Wildlife Service (listed butterfly species and host dependence); Doug Tallamy and University of Delaware research on native plants and lepidoptera; North American Butterfly Association (garden certification criteria).