Butterflies in the swallowtail family found in North America are fun to have around because they are so large and can easily be seen. And one or more species of swallowtail butterflies can be found in all states in the U.S. and parts of Canada.
The most commonly known is the Tiger Swallowtail butterflies which have both an Eastern and a Western (photo below) species that have ranges covering all of the Eastern and Western U.S. except the southwestern states. The Two-tailed Swallowtail (photo above) is one of the family that is found in those remaining southwestern states. And Jill has previously posted on this blog about both the Zebra, found in eastern U.S., and the Giant Swallowtail, that is found in various parts of the U.S.
Though they will sip nectar from many plants, butterflies are most attracted to areas that provide ‘larval host plants’–butterflies deposit their eggs on the leaves of these host plants. Caterpillars will develop from these eggs and they will feed on the plants that are specific to the species of butterfly (so it is important that insecticide not be used around these host plants, or any on which adult butterflies might feed–remember that butterflies are insects and insecticides can kill them).
One excellent plant species whose leaves are used by several species of swallowtail butterflies for egg laying is the Chokecherry, a prunus (P. virginiana) that is native to all but a few far southeastern states in U.S. and through much of Canada. Chokecherry also attracts many other birds plus other butterflies. Their blossoms are so very fragrant your yard will smell delightful. Plus some use the chokecherry fruit to make jelly (but be sure to leave some fruit for the birds as they will draw a number of species including catbirds, kingbirds and bluebirds).
Host plants for Eastern Tiger Swallowtail include the following: wild cherry (Prunus), sweetbay (Magnolia), basswood (Tilia), tulip tree (Liriodendron), birch (Betula) tree, ash (Fraxinus) tree, cottonwood (Populus) tree, mountain ash (Sorbus) tree, and willow (Salix).
Western Tiger Swallowtails use the following for host plants: cottonwood (Populus) tree, aspen (Populus) tree, willows (Salix), wild cherry (Prunus), and ash (Fraxinus) tree.
Host plants for Two-tailed Swallowtails include ash (Fraxinus) trees, hop tree (Ptelea), and chokecherry (Prunus).