We are often told that one of the best ways to encourage butterflies to visit our property is to landscape with native plants. While it's true that native plants can be great larval host plants and nectar sources for adults, many butterfly species have also adapted to non-native plants, which can also provide important support for both caterpillars and adult butterflies. In fact, according to butterfly expert Sharon Stichter of the Massachusetts Butterfly Club, some butterfly species have switched over from a native to an introduced host or nectar plant because the native is not easily available or is a less robust food source.
Writing in the August 2012 Ecological Landscaping Association newsletter, she notes that the lovely black swallowtail butterfly, which used native water hemlock and water parsnip as larval host plants in the nineteenth century, now thrives by using the more widely found non-natives, Queen Ann's lace, parsley, dill, and fennel, almost exclusively. Similarly, naturalized field clovers and meadow vetches serve as important nectar sources for the adults of many species.
Another way to provide good butterfly habitat is to let some of your property grow as meadow or grassland. But in most parts of the county, these areas need to be mowed periodically to keep them open. To benefit the most butterfly species, the meadow should be mowed no more than once a year in late fall, keeping the mower height at least 4-6 inches off the ground to avoid the overwintering larvae at the bases of plants. If possible, mow only a section of the meadow each year, in rotation, so that there is always an unmown area of refuge for insects.
For more information on landscaping for butterflies and other pollinators, go to: Ecological Landscaping Association.