On Earth Day, an update from the Caterpillar Condo

The Herb-Filled Home for Wayward Swallowtails

A freshly emerged Swallowtail (Papilio polyxenes) dries its wings next to a still slumbering roommate

It is Day 22 of the 2025 Swallowtail Season. For those following along at home, I set up my caterpillar condo on April 1st and quickly filled it with fifteen superplump stripey hippos freshly plucked from my dill and rye patch.

Was that too many? Possibly. But in the Joy Max Method, we go bold at the beginning of the season, when spring temperatures are forgiving and the herbs are their most vibrant. Those of us who know the Eye of Sauron that is the Texas summer sun respect its power with equal parts awe and strategy.

My neighbors had to cut down a large section of their magnificent red oak this winter, leaving my herb patch without its protective canopy for most of the day. Currently, it's a caterpillar jungle of munching delight - but will it remain that hospitable as temperatures creep up to hell? Time will tell.

I'm setting an ambitious goal of midwifing 50 butterflies into the world this year, which means going all-in while conditions are ideal. There's something deeply healing about watching these hungry creatures transform - a daily reminder that nature's rhythms continue regardless of our human concerns.

For those new to butterfly gardening, this early spring enthusiasm isn't just excitement - it's strategic planning. Each caterpillar that successfully metamorphoses now is one generation closer to establishing a thriving local population before the brutal heat sets in.

How's your butterfly season starting? You could begin with dill and fennel, they grow quickly in warm temperatures. Here’s a quick resource list:

My Swallowtail Seed Collection - Four herbs (Parsley, Fennel, Dill, and Rye) This is FREE for Founding Members of this Substack ☺︎

How to Raise Swallowtails: My Joy Max Guide to Butterfly Parenting

Single seed varieties (Bouquet Dill, Heirloom Bulbless Fennel, Giant of Italy Parsley)

The Caterpillar in the Rye

Notes and Observations

I currently work from home which allows me time to check the enclosure multiple times a day. Having so many caterpillars inside means there will be a daily mess. Once they start pupating, you'll need to check the enclosure at least twice a day starting at the nine-day mark to make sure you aren't accidentally keeping any butterflies hostage. So if you don't have that availability, or no one in your household does, then you can still grow the herb forest, just skip the enclosure.

The benefit of an enclosure is that you can shepherd your flock through their transformation in a safe(r) space than the wilderness of your garden. But just planting host plants is already a huge benefit to their population and a lot less work. Here is a photo of my son enjoying some fresh dill.

Season Stats

There were two inexplicable deaths in the house. I observed similar deaths in the herb patch so it’s hard to say what the variable was. Parasitic wasps? Some sort of infection? We mourn and move on. A group of five set off on walkabout for their pupation post on April 8th. That was a messy day if you remember what I told you about the gut purge they due prior to this moment. At that point, I stopped taking any new roommate applications. These caterpillars trash the place. I don’t want butterflies dragging their still-wet wings through that mess. I moved the herbs out and disinfected as best I could with alcohol wipes.

The first fifteen:
1 death early in the season
1 death in chrysalis (it just sort of deflated and turned into mush)
1 death of the last roommate. He was so vigorous but when he went on walkabout he just never stopped roving. I blamed myself that there were so many roommates that he couldn’t get a good spot. He died looking for it. Hanging upside down from the top of the tent. Tragedy.
9 Butterfly Births! 5 Female / 4 Male
3 Still Sleeping TBD

They have all been pupating for about 12-13 days each so far and are emerging now daily, usually 2-3 per day. Butterflies are also messy. I’d forgotten. The chrysalises spill out a brown liquid when they emerge so before season two starts, I’ve got to figure out how to clean this thing, otherwise the Instagram story aesthetic will suffer. But I have been documenting most of this so check it out if you are looking for some non-Bravo reality programming.

Two butterflies born on Earth Day

Female Easter Swallowtails are larger than males. They are darker and blue is the largest color plane on the wing. This beauty was easily 4” wide, the biggest baby yet.

Male Swallowtails have prominent yellow bands across the wing and are much smaller.

Beyond the Enclosure

I do take these losses hard. But just look at the beauty that's emerging! It's a lesson I'm learning daily: focus on what I can do. Focus on the tender vulnerability of life all around us. Nurture what I can. Think beyond what's just good for myself.

Whether you're raising a full condo of caterpillar cast members or simply planting a patch of dill and rue, you're creating a small sanctuary of possibility. That's incredible! That's no small thing. You are the witness to these moments that no one else gets to see. What a privilege it is. Wouldn’t Mary Oliver be proud?

Now, if you'll excuse me - I need to check the enclosure again. I think I see another chrysalis beginning to shimmer with the promise of wings.