Eastern Black Swallowtail Butterfly Life Cycle Photos
How to Raise Black Swallowtails from Egg to Butterfly
When we first started butterfly gardening, I believed that eastern black swallowtails were regular visitors to our Minnesota butterfly garden. But after years of observation and networking with other butterfly enthusiasts, I realized this was not the case…Vertical gardening ideas
What we’d been seeing mostly was the dark form eastern tiger swallowtail. A bird’s eye view of the abdomen distinguishes a true black swallowtail (pictured above) from its close relatives.
Eastern Black Swallowtails (Papilio polyxenes) are one of the most abundant swallowtail species across North America. Click here to see if they’ve been sighted in your region?
Host plants for caterpillars include common rue, curly parsley, carrot tops, golden Alexander, bronze smokey fennel, dill, celery, asparagus, and Queen Anne’s Lace.
In our garden, we’ve had the most success attracting ELFs (egg laying females) with fennel, but we stopped planting it because it attracted too many wasps. Wasps are beneficial pollinators, but in large numbers they can wreak havoc on the caterpillar population in your garden. So, we switched over to common rue and golden Alexander.
Eastern Black Swallowtail Eggs
One of the pros of fennel is that it contrasts beautifully with black swallowtail eggs to make finding them easy, considering their small size…
Unlike monarchs, eastern black swallowtails will often lay eggs on the tops of leaves, which can make them a little easier to find. However, the green-tinted eggs tend to blend in with their host plants.
Eastern Black Swallowtail Caterpillars
Our most recent black swallowtails were brought in as small caterpillars. I was not expecting to find them on our golden Alexander plant, but they were easy to see against contrasting yellow blooms. So, we took stem cuttings (with caterpillars) and placed them in floral tubes.
Tube Tip: take long cuttings so that the stem goes to the bottom of your floral tubes. That way you’ll have to refill less often.
Find Floral Tubes with holding Racks for Caterpillar Plants ⬅️
Common rue is also easy to fit in floral tubes and is also a host plant for Giant Swallowtail Butterflies.
Some people have allergic reactions to rue so you might want to handle this plant with gloves.
Fennel is a top host plant for attracting eastern black swallowtails and the feathery foliage is beautiful addition to the garden landscape…
Other host plants for black swallowtails include curly parsley, dill, and carrot tops.
Monarchs go through their metamorphosis almost twice as fast as their swallow mates. I’m often asked if they can be raised in the same enclosure. I’m not aware of any disease or in-fighting issues, but I’d suggest raising them on elevated stem cuttings to keep them separated. We also use separate mesh enclosures, but did introduce these two briefly:
As eastern black swallowtails grow, they also became more colorful. Many confuse monarch caterpillars with black swallowtails, but if you compare the caterpillars below, with the large monarch above, you can see the differences.
Also, monarchs only eat milkweed so you’ll never seem them feasting on your dill or fennel…or zizia!
Once the caterpillars are ready for the next stage, they are kind enough to let you know in advance 💩 😉
Black Swallowtail Chrysalises
Before the caterpillar searches for that perfect spot to form its chrysalis, it will purge any remaining food all over the cage floor. Thankfully, we had our caterpillar cage liner inserted on the cage floor so they purged inside that. Otherwise, it can stain the cage floor, as our eastern tiger swallowtails did multiple times in this cage:
Swallowtails will attach themselves to the cage wall, cage ceiling, stick, or host plant in two places: at the base with a silk pad and with a silk girdle around the mid section of the caterpillar:
So it looks like we’re good to go? Not so fast…
This poor swallowtail was compromised by disease or parasites. This photo was taken several seasons ago, and the caterpillar never did form its chrysalis. We’ve never had any diseases (I’m aware of) affect swallowtails. However, we’ve had caterpillars parasitized by the Trogus Pennator Wasp. If you know what happened to the caterpillar pictured above, please post a comment a the bottom of the page…
Here’s a healthy eastern black swallowtail, to take us to the next stage of the butterfly life cycle:
This caterpillar formed a chrysalis directly on its golden Alexander host plant. Green chrysalides are more common during the spring and early summer. Many believe this is a defense mechanism against predators that helps them blend in with their surroundings…
In the late summer and fall, the chrysalis colors are more likely to blend in with the tree branches that will hide them from predators over winter.
A monarch chrysalis will hatch reliably in 7-10 days, but the swallowtail family is on a European vacation schedule. They can take 2-3 weeks, or longer if they see fit. If you’re raising toward the end of the season, they may even decide to overwinter until next season.
Eastern Black Swallowtail Butterflies
Before your butterfly emerges, the chrysalis will turn dark (with yellow accent spots) revealing the butterfly inside. It’s easy notice this change with a green chrysalis, but the change is more subtle when the chrysalis is formed brown.
When the adult butterfly emerges, it will come out of the top of the chrysalis, and find a place to hang down to expand and dry its wings properly:
As with monarchs, I suggest placing eastern black swallowtail butterflies outside in a closed mesh cage for a couple hours to sunergize 🌞 them. This insures they will have plenty of energy to elude potential predators upon release.
Females typically have more blue hue in their hindwings, and less prominent yellow wing markings:
Males typically have less blue hue in their hindwings, and more prominent yellow wing markings:
Eastern black swallowtails don’t spend as much time in the butterfly garden as some others in the swallowtail family, but zinnias and obedient plant are two plants they have favored in our northern garden over the years. If you know of other BST favorite nectar plants, please leave a comment below…
Please Post Questions, Comments, or Share your Experience Raising Eastern Black Swallowtail Butterflies.
Tony, I need help!
It’s October 21, 2025, I have black swallow tail caterpillars. Raising on carrot tops were I found them. In my house, netted cage I had used for my monarchs. I have one that has gone into chrysalis, two in “j” and strangely enough about 17 more caterpillars. What should I do? Over night it was 38. Do I mice them out to my porch after they go into chrysalis for the winter? I had them outside as caterpillars and found 4 laying on the floor, they did revive with brought in and warned up. Will they know they have to go into winter mode if in the house while caterpillars? Help!
Hi Joyce, check out this post for info about:
How to Overwinter Swallowtail Chrysalides
Hi, I am new to the whole family of Swallowtails:-). But I found around 12 little guys (caterpillars) on an anise plant. One of them is larger. I have been trying to figure out whether they are Black Swallowtail or Anise Swallowtail. I searched internet for hours and I learned nothing of how to distinguish one larva from the other. Do you know? Can you help? Thank you in advance. BG
Hi BG, if you found them on anise plants, they’re anise swallowtails…congrats!
Last year, mine loved dill, fennel and parsley. Nectar was almost exclusively from zinnias and butterfly bush. This was first time I had two make chrysalides late. WHEN should I expect them to eclose here in SE Michigan???
Hi Tammy, they can be unpredictable but look for them to eclose any time once temps are consistently in the 70’s or warmer…good luck!
Yes! This is the first year I have seen them in my garden- they are all over the bronze fennel.
I plant Tithonia (Mexican Sunflower) alongside my zinnias and the Monarchs and Black Swallowtails absolutely love it. I call it the butterfly magnet flower!
Hello- I raise a few monarchs and this year found a black swallowtail on my dill, so brought it in to raise.
It made it’s chrysalis on September 3rd and I thought I would be overwintering it here in MN but it emerged today, Sept. 22nd. Is this normal?
I know nothing about Black Swallowtails, as I said I have just raised monarchs in the past. Do swallowtails migrate?
I don’t know how long we will have nice, warm weather here. How long do they live and are there still other swallowtails around here in MN?
I have plenty of late blooming nectar plants for it, but worry the weather will turn cold as MN weather is unpredictable.
Any info would be greatly appreciated!
Thanks!
Hi Shannon, it should head south, but I’m not sure if they congregate anywhere specific for the winter months or how long it will survive…I would definitely release it on a sunny day. It will know what to do from there…
Tony,
We had a few caterpillars and two of they have turned into beautiful butterflies. I have one male and one female. The male came out first. I have been feeding them sugar water from a Q-tip. My male is very lethargic and rarely moves in his butterfly enclosure. I am worried that I am not taking care of them properly. Please advise and thank you.
Hi Amy, are you keeping them because of inclement weather? If not, I would just release them:
Releasing Butterflies Safely
Hello! Your blog has been extremely helpful as I thought our caterpillar was sick and almost separated it from the rest when in reality it had purged and has now formed a chrysalis! Another cat attached itself right on top of the zipper of our cage. I forgot about it while unzipping and have dislodged his bottom silk pad. He’s still attached by the silk girdle but he won’t be able to get out of his skin without that pad attached will he? I feel awful! I actually thought about glueing it’s butt back down. 🙂 Is there a way to help it now?
It became a chrysalis in spite of having it’s silk pad detached! Unfortunately it fell onto the floor of the mesh cage and may have hit a stick on the way down. Hopefully it survived the fall. How do I rehang it? I’ll have to look around, I remember seeing something about that.
Hi Christina, there’s info about rehanging swallowtail chrysalides here:
Overwintering Swallowtails and Chrysalis Care
Very good information, thanks!
Hi Christina, I would post in this group for some ideas:
Simply Swallowtails
I’m raising my first two black swallowtail caterpillars and am finding what looks like tiny aphids on my dill. How harmful will they be to the caterpillars? I’m having a terrible time “keeping up with the aphids.” (If that is what they are.)
Hi Kristi, they are more harmful to the plants:
Short and long term strategies for stopping Aphids
I have several Black Swallowtail caterpillars on one of my Rue plants. They’ve pretty much decimated that one plant, but I have others that are a few feet or yards away. Should I pick up the caterpillars and move them to a fresh plant so they can continue to munch?
Hi Kathleen, you could just cut off the stem they are currently on and set it on the new plants.
Hi:
I have raised Black swallowtail caterpillars indoors before (they don’t do well outside – too many birds and other predators.
This year I had more than usual, and am running into a different problem: while several are already happily on a stick (or on the wall of the mesh container I have them in – works fine) and progressing normally, I have had a few, in the pre-pupa stage (i.e. no longer eating, they have had their big “dump”, and should be attaching themselves somewhere vertical), that have remained (or fallen) on the bottom of the mesh container. The 2 I left there to see if they would still move to a stick, have died. I now have 3 more doing the same thing: can they be attached to a stick or the container wall, something like you can do with a chrysalis?
Thanks,
Roberta
Hi Roberta, black swallowtails can pupate on plants, cage walls, or sticks…you could also put them inside a paper bag. If this many are dying it sounds like a potential disease or chemical exposure. I would post photos in a facebook group:
Simply Swallowtails
I’ve seen my black swallowtails nectaring on lantana, wild petunia, shrimp plant, and celosia. I had 2 that mated last summer right on the bronze fennel they hatched from, but I have never seen them nectaring on the fennel. The only butterfly I’ve seen nectaring on my fennel was a red-banded hairstreak. You are right about the fennel being an attraction for bees and wasps. I’m glad to learn from your site that rue and golden Alexander are good host plants that might not attract so many wasps. Spiders, assassin bugs, and stink bugs also inhabit the fennel and lie in wait for caterpillars and chrysalids. I currently have 50+ black swallowtail caterpillars on bronze fennel in my yard in Georgetown County, SC.
Black swallowtails ( and other caterpillars) are subject to the melt or wilt virus just as monarchs are. I learned from your links on your monarch site that this Black Death ( or NPV) virus lives in the ground and on vegetation. Caterpillars get it when they crawl through it they then turn black, liquefy, and die. I’m wondering if your chrysalis above might have NPV. I watch for black caterpillars on my fennel and remove them along with the “leaves” they are on being careful not to drop them on the ground where the virus can continue to live.
Hello, a chrysalis was formed in my butterfly keeper in early June and the butterfly (EBST) still has not emerged. About 10 days ago I noticed a blackish mass that came out of one end of the chrysalis. There was also a green-tinted liquid that dripped down the side of the butterfly keeper (the chrysalis is attached to the lid of the keeper). After days of nothing happening with emergence, I removed the chrysalis from the lid and the blackish mass fell off. The chrysalis appears to be intact. The blackish mass appears to be frass. Is the butterfly dead inside the chrysalis?
Yesterday I noticed another chrysalis that has the same blackish-mass, although much smaller than the first. This chrysalis was formed at the end of June.
What should I do with these chrysalises? Is this blackish mass frass? Thanks.
Hi Susan, I’m not sure what the issue is. If you’re on facebook, post a photo of the chrysalis in this group:
Simply Swallowtails
Could it be the melt virus (NPV)? See my comment above from Aug. 2.
Hey Tony,
This came just in time, been looking for tiger swallowtails and planted a lot of dill, parsley and fennel this year. and have some really tiny rue plants . I have been looking for them and lucky me found 4 eggs and two of them have hatched !!!! They are in one of your cages and I put the dill in a canning glass jar with saran wrap and then put the ring only back on top. poked a hole in the saran wrap and stuck the dill in. So far so good. Can’t wait to see the journey . Thanks for all that you do .
would like to add a photo ? How do I send you a photo ???
Elaine
Hi Elaine, there’s not a way to post photos on the blog, but if you’re on facebook you can post raising photos in the facebook group:
Raise More Monarchs, Less Effort
Help my black swallowtail chrysalis fell from his saddle and is laying on the bottom of the cage! What do I do ????
Hi Nancy, I would probably set it on the cage floor by a mesh wall so it can climb to dry its wings when it emerges. Post your question in this facebook group for more ideas:
Simply Swallowtails
Thanks Tony. I was concerned that it would hatch properly laying on the ground. I was thinking whether I should design a sling with thread and rehang it. But I will give it a try leaving him on the bottom of the cage ! Thx ?
Hi Nancy, there is also more info about rehanging swallowtail chrysalides in the post:
Overwintering swallowtail chrysalides and rehanging info
Hi Tony
I was wondering if you could help me. I have 10 Eastern Black Swallowtails in my big cage on my porch. 7 have chrysalis, some on the stick branches I had in the cage but others have attached themselves to the rim of the pan that was holding my parsley plants and others have attached themselves to the wall/screen of the cage.
I had used your advice when raising monarchs on how to lasso the chrysalis to move them, but I have no idea on how to do that with a Swallowtail. I don need to move them outside safely as I am leaving on a 3 week trip and I am sure that they won’t make an appearance for another week or more. Tony can you tell me how to move these beauties? THANK YOU SO MUCH IF YOU CAN. I love your blogs and all your very good information.
Kat in Central Florida
Hi Kat, I would check out this facebook group for some ideas on where to put them:
Simply Swallowtails good luck!
Thank you so much for all your time and effort explaining all the ins and outs of raising butterflies this is my second season, your emails are so informative! I haven’t seen a monarch in Cape Cod, Mass. as yet, but the common milkweed is ready for them. Thank you again.
I found a Swallowtail cat on my dill that has gone into a chrysalis in the netted butterfly tent. I’ve been checking my dill, rue, and parsley for others. I didn’t know about Queen Anne’s Lace. We have lots of that!
Hola Tony, podrias decir si la mariposa golondrina pude ser criada en la zona de Argentina? No pude encontrar informacion en internet y me gustaria probar suerte con esta especie
Muchas gracias y saludos desde Argentina
¡Hola Patricia! Disciple mi poured español. La mariposa “swallowtail” vive solamente en norte américa y centro américa. Mira este mapa,
https://www.gardenswithwings.com/butterfly/black-swallowtail
I recall as a boy finding black swallowtail caterpillars on carrot plants in the garden.
Hi Bill, they definitely like those carrot tops!
I’ve taken some black swallowtail eggs and caterpillars that I’ve found on Queen Anne’s at my grandparents camp it was fun
Hi, Tony,
Don’t know what the problem is, but I can’t open any of the black swallowtail photos on the site. Unfortunately, we don’t see many of that species in this area, only one so far this year. But our success rate with monarchs far exceeded our greatest expectations. Happy 4th!
Pam Selbert
Hi Pam, the photos are optimized, but there are a lot, and if you have a slow internet connection it could take a little time for them to load…Happy 4th to you!
Hi Tony, Thanks for all the great info. My husband and Ilive in a forest in the north GA mountains. I grow milkweed ( aquatic, tropical and common), parsley, dill and as many perennial and annual flowers as possible due to little sun and lots of shade. We have Eastern Tigers, Pipevine Swallowtails and several other butterflies but no Monarchs or Black Swallowtails. I’ve been growing host and nectar plants for two years. Previously I’ve had great success raising Black Swallowtails in Fl. Should I keep hoping for Monarchs and Black Swallowtails or concentrate on the butterflies already living here?
hi Barbara, I think it’s a good idea to concentrate on what you know is in your area first, but then shoot for the stars once your garden is more established…black swallowtails are definitely in your region, so I’m guessing you would see some sooner or later if you planted their hosts. good luck!
Hi, Tony,
Just finished watching all your pictures and explanations on the swallowtails….so informative and beautiful! Right now I have 22 Polydamus Swallowtail chrysalides and they are really on their own schedule. I much prefer the predictability of the Monarchs!
I have fennel, dill and parsley and a few Eastern Blacks have laid eggs on them, but our Florida lizards just gobble up the tasty morsels. When I have released them, I compare them to horses out of the starting gate – up and away ! Thank you for all your help and inspiration!
We currently have 8 swallowtail chrysilades and 2 monarch caterpillars still munching away. It has been such a wonderful experience to watch them grow everyday. We have pretty much all of the green chrysilades, but 2 are the dark color…..does that mean those two will not come out till next spring?
Hi April, chrysalises now should most likely hatch this summer. good luck!
I found a Swallowtail cat last Fall and have it’s chrysalis-I have kept it outside in a mesh container next to the house. Exposed but sheltered too. if it has not enclosed by now, do you think it is dead?
Thank you.
Hi Mandy, they are so unpredictable compared to monarchs. It wouldn’t hurt to spray the chrysalis with water every few days if it’s not getting moisture. good luck!
I have enjoyed these beautiful butterflies every summer on the Joe Pye Weed “Gateway” which is the tall perennial.
Thanks for posting Beverly…we grow the ‘gateway’ variety in Minnesota too, although ours grows up to about 8 feet now ?
TN black swallowtails prefer dill in my garden year after year. They also love to visit the Joe Pye Weed in my garden and along the roadside.
Thanks for sharing your experience Beth!I don’t think there are a lot in our region so it helps to hear from people who see more of them…the monarchs are usually hogging our joe pye, but I will keep an eye out for black swallowtails…
I’m so pleased to read your info on raising Black Swallowtail caterpillars!!! I brought in a tiny BS caterpillar to raise for the first time, which became fat, healthy and almost 2″. It formed a brown chrysalis which camoflaged well with the twig. I’ve been worried about the black tinges on the chrysalis. Since I didn’t see blackening on a reference photo from a butterfly book, I have been worried that it might have had a disease. Your photo looks like it may have some blackening, though. Do you have experience with this and can you advice me? Thanks!
Hi Kathy, if you are on facebook, I would post a photo of the chrysalis here. Someone should be able to help you figure out the issue if there is one:
Simply Swallowtails
Just counted 30 Black Swallowtail on our large fennel plant. One cat just starting chrysalis on the fence. Released 5 monarchs today also.
Hi..I have a question….I now have milkweed growing everywhere on my property. Of course in places that I dont want to have it.. how can I get rid of some of it? I know how important it is for monarchs but it is taking over. I am willing to keep some of it.
Thank you.
Fifi
Hi Fifi, I would pull it…common milkweed can be invasive through underground rhizomes and seeding. If you don’t want it to see I would cut off and discard those too. We are going to have to do the same….for now, the pollinators are loving it!
Common Milkweed can ba a garden thug so us best in a wild area or meadow application.
Swamp Milkweed and Butterfly Weed (also a Milkweed) are great in the garden and do not spread like the common.
I also always plant tropical milkweed which blooms all summer and does not spread. You do however need to take it out by mid-September so the monarchs do not hang around and also to cut out on disease possibilities.
I’ve been raising Black Swallowtails for years, but this is the first I’ve heard of them using asparagus as host plants. I always learn something new from this site. Can’t wait to get out to the garden tomorrow and check the asparagus! Thank you!
Hi Tammy, I’m not sure how common it is, but have seen it documented a few times. I wanted to list it, to make more people aware. Let us know if you find any eggs or caterpillars!
I have seen Black Swallowtail caterpillars on Parsley, Dill and Fennel, here in NJ.
Can’t wait to see them again this year. Black Swallowtails are the NJ official butterfly].
Gail