Feed the butterfly babies – by growing larval host plants

Some gardeners get excited at the sight of nibbled-upon leaves on their plants. But not in the "Oh, no! Where's the bug spray?" way.

Rather, they tenderly turn over the leaves and start looking for "babies" — tiny eggs or little larvae inching along. This gnarly but necessary part of butterfly gardening — growing larval host plants — is being embraced by a growing segment of gardeners.

It's a seismic shift in gardening. Even a decade ago, the thought of growing ornamental plants for the express purpose of feeding insects would have been greeted with dismay. (And in the case of milkweed, the monarch butterfly's sole host, it was a plant many farm kids were paid to pull.)

Yet without hungry caterpillars there are no butterflies. While monarch butterflies, and their need for milkweed, now grab most of the headlines, it's easy to overlook that all egg-laying female butterfly species seek out one or more select host plants that nourish their particular larvae. What can we do for other butterflies that, though not faced with the same peril as monarchs, are still looking to survive in a world of diminishing habitat?

When people think about butterfly gardens, they imagine flower beds filled with colorful blooms, and indeed that's where most adult butterflies find food in the form of nectar. However, butterfly larvae, or caterpillars, look to the foliage of these specific plants for "baby food" as they move through the four to five growth stages (called instars) before they pupate into chrysalises and then transform into beautiful butterflies.

Here's how to help some of the butterflies that regularly visit Minnesota gardens:

Black swallowtail: If you grow an herb garden, chances are you've hosted this caterpillar. This swallowtail larva dines on Queen Anne's lace and other members of the wild carrot family that includes parsley, dill and fennel. So plant plenty to share between yourself and the butterflies! At first glance the green and black striped caterpillar looks similar to the monarch caterpillar, leading people to think they've made a new monarch host plant discovery but alas, no.

Red-spotted purple: Surprisingly, some of the most important larval hosts are trees, in this case oak, black cherry, cottonwood, willow and basswood.

Mourning cloak: One of the first butterflies to appear in spring, the adults eat tree sap instead of nectar. They use black willow, weeping willow, American elm, paper birch and hackberry trees for larval hosts.

Eastern tiger swallowtail: Up North, these large, majestic black and yellow creatures raise two broods each year, with wild cherry, basswood, birch, ash and willow for hosts.

Red admiral: Nettles may be pesky for people but are preferred by these showy little butterflies. Sometimes they also use hops.

Fritillary: Some members of this ornate butterfly family rely on wild violets for raising their young.

It takes more than pretty flowers to support many butterfly species. Who knew?

Trees, grasses and even weeds are all vital parts of the picture. Gardeners who want to not only attract butterflies to their garden but also maintain their presence by supporting the reproductive cycle need to look at their yards in a whole new light.

In addition, think twice before you use pesticides. Insecticides don't discriminate between harmful pests and butterflies. How often I hear someone say, "There's some kind of worm eating my" plant. First identify the plant and the pest before you reach for that spray can. Then do an internet search for the plant, along with the term "larval host plant," to make sure that "worm" isn't a butterfly in the making.

Decide if you can tolerate damage if it is merely cosmetic and temporary rather than threatening to the plant.

Finally, see if it's possible to leave some weeds with wildlife habitat value such as thistle, violet and nettles in unused or wild edges of your property.