11/29/2025
Here’s another reason to “leave the leaves” and not mulch or burn them this fall. In their last act as a caterpillar, Eastern Tiger Swallowtails (Papilio glaucus) often crawl down to the base of their host tree and pupate in the leaf litter or dangling from twigs on a tree or on the ground. At this stage, the brown caterpillar and pupa blend in well with the detritus and a light covering of fallen leaves insulate the pupa from cold winter temperatures.
If you want to see more of these beautiful butterflies in your yard next spring, here’s something to consider with your leaves. If you’re going to pick them up, gently blow or rake your leaves into a planting bed or wild space on your property. Spreading them out in a “fluffy” layer of loose leaves that’s less than 12 inches deep is best (think of the typical leaf depth in a hardwood forest), but this may not be manageable for all homeowners. The leaf litter will allow any Eastern Tiger Swallowtail pupae attached to the underside of the leaves to have a chance at successfully overwintering and then emerging from the leaf litter next spring.
Given their beauty and abundance, it’s easy to see why Eastern Tiger Swallowtails are the state butterfly of Georgia, South Carolina, North Carolina, and Virginia.
