The Joy Max Guide to Raising Swallowtail Butterflies
Papilio polyxenes
In nature, only 1 in 100 butterflies survive to adulthood. Your care can boost those odds.
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?
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 because
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.
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!
This collection includes:
Fennel: The Crowd Pleaser
Popularity Rating: Butterfly Michelin Star ★★★
Growing Notes: Fennel doesn’t really play well with other crops, so give it its own corner of the garden
Fun Factor: Tall, feathery, and dramatic. You can also use the cut flowers in arrangements.
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 it produces flowers 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 also is 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 so until you know if you are sensitive to it, make sure you wear gloves when handling it.
Parsley: The Reliable Backup
Popularity Rating: "Better than nothing" ★ When I grow the other herbs, I never find caterpillars on my parsley. But maybe that is just the butterflies in my neighborhood.
Growing Notes: Takes a little while to get growing but then really takes off and is even perennial in my garden.
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.
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, get more than one enclosure.
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.
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.
Daily Caterpillar Care:
Provide fresh cuttings each morning if you can (when plants are most hydrated)
Cut entire stalks where caterpillars are already munching.
Place stems in water immediately
Clean frass (caterpillar poop).
Keep the caterpiller on the same herb diet you found them on.
The Great Caterpillar Appetite
Prepare to be astonished by how much these tiny creatures eat. One day you'll 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 tiny green or 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
As emergence time approaches:
The chrysalis becomes increasingly transparent
With green chrysalides, you'll clearly see the butterfly wing patterns developing inside
Brown chrysalides make this a bit more of a "surprise party"—changes are subtler.
Emergence Day!
The chrysalis will split open
The butterfly will emerge with crumpled, wet wings
It will hang upside down, pumping fluid into its wings
This process takes 2-3 hours—DO NOT DISTURB during this critical time.
Once wings are fully expanded and dry, your butterfly is ready for release
Release Day: Saying Goodbye
To give your butterfly the best start in its new life:
Choose a warm, sunny day (above 65°F/18°C)
Release in the morning or early afternoon
Find a spot near flowers for an immediate nectar source. I also do this to encourage them not to leave (they always do).
Take a moment to appreciate what you've accomplished (and maybe shed a tear—I won't judge).
The Circle of Butterfly Life
Female butterflies will live 2-4 weeks, during which time they'll mate and lay eggs to start the cycle again. Males typically live a bit less time, but they make up for it with fabulous flying displays to impress the ladies.
Troubleshooting: When Things Get Weird
Common Issues:
Disappearing Caterpillars: Likely predation if outdoors, 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!