A large-scale study published in Science in 2025 documenting sharp declines in butterfly populations across the United States has prompted gardeners to rethink what it means to create a “butterfly garden,” professional horticulturists say. Callyn Owen and Kate Herlihy, who run The Nursery at Mount Si in North Bend, Washington, warn that well-intentioned plantings can sometimes do more harm than good if they are not matched to the local species those gardens are meant to support.
Owen and Herlihy say homeowners too often fixate on monarchs — a familiar flagship species that has drawn conservation attention but is not present in every region. Monarchs are in rapid decline and remain a high-profile concern, yet they have not been formally listed as endangered despite ongoing petitions. Many gardening guides default to the single prescription “plant milkweed,” which is essential for monarch caterpillars, but that advice can be misplaced outside monarch migration corridors and may overlook the needs of other native butterflies.
Before buying plants, the gardeners recommend first learning which butterflies are native to a given region. Resources such as the U.S. Fish and Wildlife Service migration maps and databases like Butterflies and Moths of North America can help homeowners identify local species and the specific host and nectar plants those species require. In the Pacific Northwest, for example, Owen and Herlihy point to species such as the Western tiger swallowtail, Lorquin’s admiral and the echo azure, each of which depends on different host plants than the monarch.
The distinction between host plants and nectar plants is central to their advice. Host plants — the species on which butterflies lay eggs and on which caterpillars feed — vary widely: milkweed supports monarchs, but other butterflies rely on stinging nettle, fruit trees, native grasses or particular herbaceous plants. Nectar plants, used by adults for food, are generally broader in their appeal; suggested choices include yarrow, valerian, echinacea and salvia. “Don’t be alarmed if you notice your host plants getting devoured by caterpillars in your garden — that’s what they’re for,” Owen said, urging identification rather than immediate spraying when larvae appear.
Owen and Herlihy also offered practical habitat tips to boost a garden’s usefulness to butterflies. Butterflies require water and minerals but cannot land on open water surfaces, so a shallow basin or a birdbath with rocks above the waterline makes an effective drinking station. They recommended avoiding chemical pesticides that kill eggs, caterpillars and adults, and adding supplementary food sources such as overripe fruit or a dedicated butterfly feeder; some species will also take sugar or diluted honey solutions. Small, dark flat stones can provide “warming surfaces” for dorsal basking — butterflies need to reach body temperatures around 86 degrees Fahrenheit to take flight, according to Lewis Ginter Botanical Garden guidance cited by the gardeners.
Taken together, the advice shifts the emphasis from planting a single signature species to building localized, species-aware habitats. With butterfly declines now documented on a national scale, Owen and Herlihy said tailored plantings, reduced pesticide use and simple garden features can make suburban and urban yards more valuable refuges for a wider range of native butterflies.