The Joy Max Guide to Raising Swallowtail Butterflies
Papilio polyxenes
This is a male Swallowtail butterfly.
Welcome to the wild, wonderful world of butterfly parenthood! As an experienced butterfly doula, I’m here to help you bring these fluttering wonders into the world. You're about to embark on a journey that combines gardening, wildlife conservation, and pure wonder. This guide will walk you through every magical (and occasionally messy) step of the journey, from tempting mama butterflies to your garden to waving farewell as their babies take their first flight.
Why Grow Your Own Host Plants?
If you spot any native milkweed at nurseries in the spring, like Antelope Horns, definitely pick some up as they are host plants for endangered Monarch Butterflies. You can raise them as well!
Growing your own herbs isn't just economical—it's essential for successful butterfly ranching. These babies are going to be very hungry. Growing their food from seed allows you to easily and cheaply grow way more than your family can eat. You want to grow enough to share with these very hungry hippos. The herbs in my collection are great choices:
They're butterfly magnets: Female swallowtails can smell these plants from impressive distances. She will find your garden and, if you are lucky, you can even watch as she lays her eggs.
They're chemical-free: Store-bought herbs or nursery plants might be treated with pesticides that turn your well-intentioned butterfly nursery into an accidental butterfly graveyard. That is not to say that you shouldn’t buy a transplant if you want to get a head start, but make sure to ask at the nursery if they are organic. Do not buy herbs from big box stores like Lowe’s or Home Depot.
This collection includes:
Fennel: The Crowd Pleaser
Popularity Rating: Butterfly Michelin Star ★★★★
Growing Notes: Fennel doesn’t play well with other crops, so give it a devoted corner of the garden where it won’t cause trouble.
Fun Factor: Tall, feathery, and dramatic. You can also use the cut flowers in arrangements. The heirloom version included in the collection, doesn’t produce bulbs, even more foliage for the cats.
Note: Of all of these herbs, in my experience, this is the most popular with Swallowtails. Plant a good amount of it since you will be harvesting it often.
Dill: The Multitasker
Popularity Rating: Very High ★★★★
Growing Notes: Quick-growing and easy from seed. It also re-seeds easily.
Bonus Features: Comes in very handy in the kitchen during the spring and summer. Potato salad, ranch dressing, fresh cucumber salad, yes please! And, like fennel, when it flowers, the strange, explosive look of them can be lovely in bouquets.
Rue: The Exotic One
Popularity Rating: Good ★★★ (especially if you are a witch)
Special Power: The only herb in the collection that is also host to Giant Swallowtails— North America’s largest butterfly!
Growing Notes: Can be shaped into a lovely little hedge for garden borders
Important Warning: Rue can irritate some people’s skin. Until you know if you are sensitive to it, make sure you wear gloves when handling. It should be avoided entirely by pregnant women.
Parsley: The Reliable Backup
Popularity Rating: "Better than nothing (with butterflies anyway)" ★ When I grow the other herbs, I never find cats on my parsley. Maybe that is just the butterflies in my neighborhood, but it is not their fave.
Growing Notes: Parsley takes a little while to get growing, then really takes off. It re-seeds and has become perennial in my garden. It’s so hardy, thriving in the heat of summer and through freezes. If you want to keep some edible, keep it tripped to avoid bolting.
Best Feature: Even if butterflies snub it, your kitchen will benefit. Parsley goes with many types of food and looks beautiful as a final garnish. It really ties a dish together! It’s nice that it grows year round. I love it on stew and steak and potatoes in the fall and fish with lemon in spring!
From Egg to Caterpillar: It Begins!
Swallowtail eggs look like yellowish pearls on the undersides of leaves. I wait until they hatch into tiny caterpillars to collect them for my nursery unless the egg is on a rue plant as I don’t want to miss any Giant Swallowtail babies. Those eggs are a darker orange-y color.
Swallowtail Instar Stages
Swallowtail caterpillars go through five stages of growth in about 3 to 4 weeks, called instars. They start out as teensy black babies with a white “saddle” in the middle of their body. They look like bird droppings by design. Giant Swallowtails continue to look like splotched droppings even as they get large but Black Swallowtails gradually turn into the iconic fat caterpillars with black bands and yellow dots that we know and love.
Big Decision: Garden or Enclosure?
Option 1: Free-Range Caterpillars
Pros: Natural environment, a lot less work for you
Cons: Low survival rate due to many natural predators. Just growing host and nectar plants is a great way to support these animals so don’t feel like you have to use an enclosure.
Option 2: Caterpillar Condo (Enclosure)
Pros: Up to 90% survival rate, front-row seats to the miracle of metamorphosis
Cons: More hands-on care is required, and you'll become intimately familiar with caterpillar poop. Also, some of the caterpillars, despite your best efforts, will likely pass away, sometimes weirdly gruesomely. If you are doing this as an experiment with kids, consider you may have to confront some heavier subjects than the whimsey suggests.
Enclosure Basics: Setting Up the Nursery
What You'll Need:
A mesh enclosure. I bet if you are handy you could build a cool one. I love this one on Etsy. For now, I use a pop-up habitat. Some experts prefer these to built enclosures as they can be easily sanitized. If you want to raise more than ten at once, or raise another type of butterfly, like Monarchs, get a second enclosure. This is the large one that I use.
Small container for water to hold plant cuttings. Finally, a use for all those big jars you’ve saved! You probably don’t want to use anything too nice. They are going to get shit on. If you have something heavy, that will help anchor the enclosure and also keep it from tumping over in a strong breeze.
Paper towels, newspapers, or a poo poo tray for the bottom (you'll thank me later)
A safe spot away from direct sun but with good light. I keep mine on the back porch in deep shade in the summer.
Some rocks or bricks to anchor the enclosure and protect it from wind.
Daily Caterpillar Care:
Provide fresh cuttings each morning if you can (when plants are most hydrated)
Cut entire stalks where caterpillars are already munching. Keep the cats on the same herb diet you found them on. That’s what they know and like.
Place stems in water immediately
Clean frass (caterpillar poop).
The Great Caterpillar Appetite
Prepare to be astonished by how much these tiny creatures eat. One day, you have a lush herb garden, and the next, you'll have stems that look like they went through a tiny locust plague. Some facts to prepare you:
A single caterpillar can eat its body weight daily
In their final growth stage, they eat CONSTANTLY
You will find yourself running to the garden for more cuttings, wondering if you should have planted an entire farm. Especially if you are raising more than 8 caterpillars at once.
The Poop Situation (Yes, We Need to Talk About This)
Caterpillars are, quite frankly, poop factories. Some fascinating frass facts:
Frass looks like round black pellets.
A healthy caterpillar produces frass constantly.
The amount of frass seems physically impossible given the size of the caterpillar.
Daily cleaning is necessary. Putting newspaper at the bottom of the enclosure is very helpful.
The "Great Purge" and Chrysalis Prep
When your caterpillar is ready to pupate, you'll witness what I affectionately call "The Great Purge"—a dramatic emptying of their digestive system that's both fascinating and disgusting.
After this lovely event:
They'll stop eating and start wandering
Look for a suitable spot, usually high up in the enclosure
Form a J-shape with their body and go very still
Spin a silken thread to anchor themselves from the middle like a man on a telephone pole
Chrysalis: The Waiting Game
The chrysalis stage is where patience becomes a virtue:
Green or brown chrysalides blend perfectly with their surroundings (nature's camouflage at its finest)
This stage typically lasts 10-14 days in summer
Late season chrysalides may "decide" to overwinter (butterfly hibernation mode)
Resist the urge to touch or move chrysalides—they know what they're doing! The exception being if you find one outside and you want to move it to an enclosure. I’ve noticed some birds will ignore the caterpillars but immediately gobble up the chrisalides. Supposedly the herb diet of the instars make them taste bad to birds but once they transform, delicious!
The Grand Finale: Butterfly Emergence
Take a moment to appreciate what you've accomplished (and maybe shed a tear—I won't judge). Keeping a little Butterfly Journal will let you keep a record of all your experiences and the releases of all your children.
Female Swallowtail. Larger and with prominent blue and less yellow.
Male Swallowtail. Smaller. Much more yellow throughout, especially banded across the wing.
Common Issues:
Disappearing Caterpillars: Likely predation if outdoors (anoles love them) or possibly cannibalism among very hungry caterpillars (yes, that happens!)
Chrysalis Looks Wrong: Dark or discolored chrysalides may indicate parasitic wasps or disease.
Butterfly Can't Fly: Wings may not have dried properly; provide sugar water (1 part sugar to 4 parts water) on a sponge and give it more time.
Final Thoughts
Congratulations! You've now joined the secret society of butterfly midwives. There's something truly magical about releasing a creature you've helped bring into the world. In times that feel uncertain, watching this ancient cycle of transformation reminds us that change—while sometimes messy and unpredictable—ultimately leads to something beautiful.
Remember: Every butterfly you release is a small but meaningful contribution to our local ecosystem. Pat yourself on the back, butterfly hero!