Seek out native plants to lure elusive pipestem swallowtails to your yard | Sally Scalera

On June 11, I wrote an article inquiring if anyone had pipestem swallowtails breeding in their yard.

I received an email from a reader who said she had purchased a Dutchman’s pipevine from a native nursery, but she was told by a friend that the plant was invasive and toxic for the caterpillars and that she should dig it up. The photo attached to her email did show the non-native species of Calico flower, Aristolochia elegans (also incorrectly called A. littoralis.)

I checked our IFAS Assessment website, assessment.ifas.ufl.edu, to see if Aristolochia elegans, Calico flower, is considered invasive here in Florida. When the page came up, a graphic heat map of the southeast U.S. showed the climate suitability for this species.

Most of the peninsula of Florida was dark red for our climate's high suitability for this Aristolochia species to spread throughout most of the state.  As a result of the last assessment, completed in 2016, for North, Central and South Florida, there is a red bar that says, “High Invasion Risk,” so we do not recommend planting this species.

I expect that in 2026, the plant will be reassessed, and I expect the red bar to say “Invasive” for North, Central, and South Florida.

I then looked for information to see if Aristolochia elegans is toxic for pipestem swallowtail caterpillars. When I searched the internet for information, The Florida Wildflower Foundation website for Aristolochia elegans stated: “The non-native Elegant Dutchman’s pipe (A. elegans), also known as calico flower, is dangerous to pipevine swallowtail larvae. While the plant is attractive, it is distasteful to the larvae who will die of starvation rather than eat it.”

I then wondered, if this is the most common species planted, maybe caterpillars will eat it because they have no other choice. After the first article ran, I emailed our Lepidoptera Program director and associate curator at the Florida Museum of Natural History in Gainesville. I asked him if A. elegans is toxic to pipestem swallowtails, and he said yes.

In the first article, I asked butterfly gardeners who were growing Aristolochia to email me and let me know if they had pipestem swallowtail butterflies breeding on their vines. I received emails from 20 butterfly gardeners from around Brevard County and all over the state, including Charlotte and Broward County, Englewood and Miami Beach.

As the emails continued to come my way, I became good at identifying what type of caterpillars they had, since very few emails had photos of butterflies. I also sent in some plant samples for identification at our Herbarium.

The consensus is that those who responded to my article were either growing Aristolochia gigantea (the flowers are large, measuring 5 to 8 inches long and up to 10 inches wide) or A. elegans (the flower is 4 inches long or less.) As time passed, it became apparent that everyone only had polydamas caterpillars, which was logical since both Aristolochia species that the butterfly gardeners were growing are toxic to the pipestem swallowtails.

At this point, I would be surprised if we have any pipestem swallowtails breeding in a Brevard County landscape. From what I have been told, which is obviously only a tiny percentage of butterfly gardeners, the only Aristolochia species available at garden centers (and even some native nurseries) are the non-native toxic species, Aristolochia gigantea and A. elegans.

I decided to check out the Butterflies and Moths of North America website (butterfliesandmoths.org), and decided to check that out. I discovered that the only record for a siting of a pipestem swallowtail in Brevard County was done on Dec. 31, 2004, without a photo, and the data source was the USGS – Northern Prairie Wildlife Research Center.

I couldn’t really take that sighting seriously, because there was no photo, and there were no other posted sightings along the East Coast of Florida. I believe that the pipestem swallowtail butterflies could be here in Brevard County, but they probably will not be found where humans live.

Since writing the first article, I a friend gave me three small Aristolochia serpentaria plants, a species native to Brevard County and most of the peninsula. I also purchased the Florida native Aristolochia tomentosa from a local native nursery that purchased the vines from a native nursery in the Florida panhandle.

Ironically, I recently saw a small black butterfly flitting around the vine, though I couldn’t see the markings. The next time I went out on the back porch, I checked the leaves and found small yellow eggs on both species of plants. Once again, more evidence of the polydamas butterfly.

In addition to my two native Aristolochia species, I want to look for the pipestem swallowtail’s favorite (and possibly only nectar sources) that will grow here in Florida, which include thistles (Cirsium horridulum and C. nuttallii), beebalm (Monarda punctata), phlox, wild lantana (Lantana involucrata,) petunias, beach verbena (Glandularia maritima) and sky-blue lupine (Lupinus diffusus).

Soon the temperatures will cool off, and then I will go hiking to see if I can find the pipestem swallowtails in some of the natural areas throughout the county.

It would be neat to replace the non-native and toxic Aristolochia gigantea and A. elegans with our native species. But that will take some time to get enough of the Florida native species available at local nurseries. Until then, I will try to make my backyard a pipestem swallowtail haven.

Sally Scalera is an urban horticulture agent and master gardener coordinator for the University of Florida’s Institute of Food and Agriculture Sciences. Email her at [email protected].

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This article originally appeared on Florida Today: Invasive vines can be toxic to pipestem swallowtails; instead go native