How to welcome butterflies and entice them to stay in your garden

Fragile, beautiful and fascinating, butterflies flutter their way into our gardens and seem to just as quickly wing their way out.

It isn’t because they necessarily want to leave, said Heather Stoven, an entomologist with the Oregon State University Extension Service. Rather they don’t find what they need to park themselves permanently.

When butterflies change from egg to larvae, or caterpillar, they come out ravenous and with chewing mouthparts, two things that set them up to damage plants, a condition gardeners must tolerate or forgo butterflies except in the most ephemeral way.

Fortunately for the gardener – not at all fortunate for the butterfly – only a few plants qualify as nutrition for the caterpillar, sometimes just one. These host plants must be present, Stoven pointed out, or the caterpillars starve to death. (See below for some common butterflies and their preferences.)

“If you see a weird worm creeping along one of your plants, don’t kill it until you have identified it,” she said. “It may well be a butterfly caterpillar, maybe a rare one that you didn’t expect.”

In addition to adding host plants – and tolerating the caterpillars’ nibbling – you’ll need to plant some of the nectar plants favored by adults. Many of these – zinnias, various daisies, asters, goldenrod and milkweed – may already have a place in the garden. Since butterflies are nearsighted, Stoven said, it’s best to plant one color of one species in a swath; a block of blue asters for swallowtails or a yellow moon of goldenrod for red admirals.

Fragrance plays a part, too, so don’t forget the sweet smells of lavender, mint, sweet William and honeysuckle. Around the nectar and host plants, it’s important to provide taller plants to act as protection from wind. During winter, shelter becomes more important for hibernating adults and caterpillars, who like to live in crevices in trees, walls, under mulch or leaf letter, even in empty sheds.

And somewhere there must be a sunny spot for the butterflies to warm their blood. They rarely take flight when temperatures are below 60 degrees, Stoven said. Water, too, is essential. Design a butterfly puddle by sinking a shallow dish right up to the lip in the ground and fill it almost to the top with wet sand, which they’ll sip from.

And the usual reminder: Using chemicals in the garden is counterproductive when trying to attract wildlife.