|Western tiger Swallowtail (Papilio rutulus) nectaring on Purple Sage (Salvia leucophylla)|
Nothing is more enchanting than the appearance of large butterflies in our gardens. July is typically a busy butterfly month, but we’ve been watching the Western Tiger Swallowtails since spring. If you live in the western United States you may be enjoying them as well. To learn more about attracting butterflies to your garden see our June 2012 posting (http://mother-natures-backyard.blogspot.com/2012/06/butterfly-gardens.html ).
The Western Tiger Swallowtail ranges through much of western North America from N. Dakota south to New Mexico; west from British Columbia, Canada to Baja California, Mexico. The species is similar to the Eastern Tiger Swallowtail (Papilio glaucus) of eastern N. America and is found mostly between sea level and 5000 ft. (1500 m.). The tiger swallowtails were formerly included in the genus Pterourus.
Many westerners recognize this butterfly on sight - it’s large, distinctively colored and relative common. While actually at home in riparian woodlands and stream sides, it’s not unusual to see these butterflies in gardens and city parks. One thing is certain: you’re more likely to see them in places that have food for their larva (caterpillars): Willows, Cottonwoods, California Sycamore (Platanus racemosa) and ash (Fraxinus spp.). That’s why we have so many Tiger Swallowtails in Mother Nature’s Backyard.
Two other swallowtail species visit western Los Angeles county gardens (see above). The Giant Swallowtail is a large black butterfly with a prominent yellow triangle on its open wings. The Anise Swallowtail, common in some neighborhoods, looks like a large yellow butterfly wearing a set of heavy black shoulder-pads with 3 short yellow stripes. The Pale Swallowtail, which has similar markings to the western tiger swallowtail, is black and white (rather than black and yellow) and is rare in gardens.
- Plant their favored plants.
Adult (nectar) plants (relatively simple to provide)
· California native plants: California buckeye (Aesculus californica); native dogbanes (Apocynum species); native Milkweeds (Asclepias fascicularis; A. eriocarpa; A. speciosa); native Milkvetches (Astragalus species); Cobwebby thistle (Cirsium occidentale); Yerba Santa (Eriodictyon spp.); Dunn’s Lobelia (Lobelia dunnii var. serrata); perennial Mints (Monardella lanceolata ; M. linoides; M. macrantha; M. villosa); Penstemons; Salvias (especially Purple Sage, Salvia leucophylla, in our garden); Wooly blue-curls (Trichostema lanatum)
· Other garden plants: abelia, agastache, butterfly bush (Buddleia), lilac, lillies, mints, zinnia
Larval (host) plants (require a little planning)
· California native plants: cottonwoods, poplars and willows are too big and invasive for most yards. Try instead native White alder (Alnus rhombifolia), native Prunus species like Hollyleaf & Catalina Island cherries (Prunus ilicifolia), Desert Peach (Prunus andersonii), Desert Almond (Prunus fasciculata), Desert Apricot (Prunus fremontii), native plums and Western chokecherry (Prunus virginiana var. demissa) and California ash (Fraxinus dipetala).
· Other garden plants: anything in Prunus family (cherries; plums; peaches; nectarines; apricots)