Prunus americana is a documented larval host for the Eastern Tiger Swallowtail and other butterflies; the Lady Bird Johnson Wildflower Center notes the plants "are a host to many butterflies," and Missouri Botanical Garden lists the species among host plants for the Eastern Tiger Swallowtail.

The Lady Bird Johnson Wildflower Center lists black cherry as a larval host for the Eastern Tiger Swallowtail; Prunus serotina is one of this swallowtail's key native host trees across the East.

The Lady Bird Johnson Wildflower Center lists black willow as a larval host plant for the Eastern Tiger Swallowtail (along with the Acadian Hairstreak, Mourning Cloak, Viceroy, and Red-spotted Purple — willows are among the most important larval hosts of native North American trees).

The Lady Bird Johnson Wildflower Center lists eastern cottonwood as a larval host for Tiger Swallowtail (along with Mourning Cloak, Red-spotted Purple, and Viceroy) — poplars and cottonwoods are well-known caterpillar host trees.

The NC State Plant Toolbox documents Prunus domestica as a larval host plant for the Eastern Tiger Swallowtail (Papilio glaucus).

Both sources document fennel as a larval host for "certain swallowtail butterflies" without naming each species; swallowtail host use is recorded here as the genus-level relationship the sources state.

Willows (Salix) are a documented larval host for the eastern tiger swallowtail among the many Lepidoptera that use the genus.

The Lady Bird Johnson Wildflower Center lists quaking aspen as a larval host for the Eastern Tiger Swallowtail (and the Viceroy). Aspens and poplars are well-documented butterfly host trees.

NC State Extension documents Prunus avium as a larval host plant for the Eastern Tiger Swallowtail (Papilio glaucus).

NC State documents tulip tree as the primary larval host for Papilio glaucus, supporting three flights in the deep south (February-November) and one in the north (March-September). The wedge-relevant relationship for eastern butterfly-garden design: planting tulip tree is among the most direct ways to support local eastern tiger swallowtail populations.

Willows (Salix) are among the documented larval host trees of the eastern tiger swallowtail across its range; Salix babylonica is a non-native willow that can serve the same role where planted.

NC State Extension lists the flowers as attracting butterflies. The long, narrow nectar tube favors long-tongued butterflies such as swallowtails; mapped here as a representative documented butterfly visitor rather than a recorded specialist relationship.

Missouri Botanical Garden PlantFinder lists cardinal flower as attracting butterflies; large swallowtails with long proboscises are among the few insects that can reach the nectar in the long red tube.

Missouri Botanical Garden PlantFinder notes the flowers are a nectar source for butterflies; large swallowtails are typical visitors to spring-blooming Appalachian rhododendrons, though the source does not name species.

The Lady Bird Johnson Wildflower Center flags Humulus lupulus var. lupuloides as a plant that attracts butterflies; the specific documented larval hosts (Question Mark and Red Admiral) are not yet in the Plotwright wildlife catalog, so no host-larvae relationship is asserted here.

Missouri Botanical Garden PlantFinder lists common lilac as attracting butterflies; the fragrant spring panicles are a nectar source for swallowtails and other early-season butterflies.

Missouri Botanical Garden PlantFinder lists daylilies as attracting butterflies; large swallowtails such as the eastern tiger swallowtail nectar at the open flowers.

Missouri Botanical Garden PlantFinder lists the species under "Attracts: Butterflies" for its showy fragrant spring flowers; the specific butterfly species are not named, so this is mapped as a plausible nectar visitor rather than a documented host relationship.

The Missouri Botanical Garden PlantFinder and NC State Extension both report that the showy flat-topped flower clusters of Spiraea japonica attract butterflies for nectar. Mapped to a representative widespread eastern nectar-feeding butterfly; the sources document butterfly attraction at the category level rather than naming species.

Missouri Botanical Garden PlantFinder lists the flowers as attractive to butterflies; lantana is a widely used nectar plant for large swallowtails, though MBG names butterflies only as a group rather than this species.

Missouri Botanical Garden PlantFinder flags the showy spring flowers under "Attracts: Butterflies" without naming species; mapped as a plausible nectar visitor rather than a documented host relationship.

NC State notes the flowers attract butterflies; sugar maple's late-spring bloom timing fits the first eastern tiger swallowtail brood.

Eastern tiger swallowtails work the tall domed flower clusters concurrently with other large butterflies; the late-season bloom timing makes joe-pye one of the few reliable nectar sources during the second swallowtail brood.

NC State lists "butterflies" generically; eastern tiger swallowtails are among the documented spring visitors on woodland phlox stands.

Missouri Botanical Garden PlantFinder lists Prunus × yedoensis as attracting butterflies; the profuse early-spring bloom is an early nectar source for swallowtails and other butterflies.