Parsley can be started inside or seed scattered outside to come up later as a potential spring host for Black Swallowtails who will be coming to nectar on Azaleas in late March. Beds can be laid out now, paths put into place and shrubs planted.
What butterflies prefer depends on what is available. Echinacea is listed as a nectar plant. It's popular in spring before more enticing plants start blooming in summer, ignored later.
The same is true of vitex.
When I discover a popular plant, I plant lots of it. Lantana planted along the edges of the garden on the west side near the open highway right of way attracts many different species. Lantana camara blooms well when the weather gets extremely hot and dry. Lantana montevidensis blooms best in cooler spring and fall and doesn't die back as much as L. camara, which disappears with the first freeze.
A pair of Zebra Swallowtails on Lantana.
Lantana is frequently visited in summer by the floaty zebra swallowtail, which drifts on over to a native Asimina triloba that planted itself in a great spot for caterpillars.
PawPaw in Bloom, Zebra Swallowtail host plant.
Tropicals like Pentas, Stachytarpheta and Tithonia are popular nectar plants with Swallowtails of all kinds and Gulf fritallaries.
Tithonia is popular with Monarchs.
Pride of Barbados must be started from seed inside, late winter, to bloom in summer.
Native gaillardia is popular with fritillaries and some tiny checkerspots.
Sites abound on the web to discuss which host plants attract which butterflies. I've noticed that native plants vary among states and regions.
Spicebush is usually listed as the host for Spicebush swallowtails. Here they are found on Sassafras, another aromatic.
Tiger Swallowtails, Georgia's State Butterfly, are hosted by wild cherry in my garden; elsewhere they seek out sweet bay or tulip poplar. Tigers appear with azaleas in early spring, then return later when other nectar plants are blooming.
Painted Ladies visit rabbit tobacco, thistles and peavines to lay eggs, by availability.
Buckeye larvae may be found on snapdragons, plantains and toadflax, where available. In fall, Slender False Foxglove, Agalinis tenuifolia acts as a late host and nectar plant for Buckeyes. Goldenrod is another nectar source for fall butterflies.
Sulphurs lay eggs on various hosts, including both wild and cultivated cassias.
There are many other nectar sources; zinnias are popular with butterflies from summer through fall. Butterflies, their hosts and nectar sources fill entire books. Minno and Minno's book was recommended to me as a good book for southern garden butterfly information.
Information on Butterfly hosts was obtained from Ichauway Plantation, site of the Joseph W. Jones Ecological Research Center and by personal observation.