Asclepias Incarnata

Swamp Milkweed for Monarch Butterflies
and Caterpillars

Asclepias incarnata: Swamp milkweed, Swamp silkweed, Rose milkweed, White Indian hemp

The BEST Native Milkweed for Butterfly Gardens? Swamp milkweed doesn't need to be grown in a swamp, but it does prefer moist soil. It doesn't spread through underground rhizomes so it won't take over your garden. It has a long summer bloom period that attracts many pollinators, and it receives many monarch eggs over the season. Asclepias incarnata is also a fantastic option for your container garden. More info and photos...
Swamp Beauty

Plant Specs:


  • Takes over for fading common milkweed in summer
  • Popular nectar source for monarchs and other pollinators
  • Plays well with others, not an aggressive spreader
  • Easy to start from milkweed seeds
  • Sweet but subtle vanilla scent
  • Makes a great cut flower with its long lasting blooms
  • can use stem cuttings to raise monarch butterflies
Monarch Egg on Red Swamp Milkweed Buds
Swamp Egg


  • Another milkweed species that aphids adore
  • Needs more moisture than other milkweed
  • Tiny pollinators buzzing around this can get annoying…however, this isn’t really a con since they’re pollinating your milkweed
  • Leaves are thin and dry out quickly when picked to feed monarch caterpillars

Plant Propagation:

  • Sow seeds directly in fall or spring
  • Start seeds indoors 2 months before final frost- cold stratification required
  • Winter sow for a natural cold stratification
  • Divide plants in late spring
Swamp milkweed works well as a container garden milkweed and attract butterflies with its pinkish, nectar-rich-blooms, while its leaves sustain monarch caterpillars. If you're in a dry region, potted swamp will probably perform much better than its garden grown siblings, but incarnata is really a great container idea for gardeners across North America.
Surprisingly Good in Containers

Swamp Growing Tips:

  • Slow release fertilizer is optional. Over-fertilization can inhibit flowering
  • Second year plants are a great option for growing in containers (not rhizomatous)
  • Cut off milkweed pods to prevent fall seeding
  • or bind them shut with twist ties or rubber bands if you want to collect asclepias incarnata seeds

Asclepias incarnata (swamp milkweed) is one of the best milkweed varieties for North American gardeners because it serves as nectar plant for adult butterflies and is also a host plant for munching monarch caterpillars. It's one of the few milkweed species that doesn't spread through underground rhizomes. More swamp photos, info, plants and seeds...

Pollinator Plus:

Asclepias incarnata also attracts buckeyes, bumblebees, eastern tiger swallowtails, fritillaries, hairstreaks, honey bees, hummingbird moths, hummingbirds, skippers, spicebush swallowtails, and more… (If you know of others, please comment below.)

The beautiful blooms of Asclepias incarnata (swamp milkweed) attract many species of butterflies, hummingbirds, and bees to the garden with thier long summer bloom period. More swamp milkweed photos and info...
Tiger in the Swamp




3. Find Swamp Milkweed on Amazon

The links above also includes popular cultivars like ‘ice ballet’ (white), ‘Cinderella’, and ‘soul mate’. These have all been reported to attract monarchs too.

25+ Milkweed Plants Ideas for North American Butterfly Gardens

Please post below if you have any questions or comments about growing Swamp Milkweed in your butterfly garden:


  1. Steff Mandarino says

    I live in the Atlanta area and planted asclepias incarnata in my garden about 5 years ago, right next to my asclepias tuberosa. The tuberosa blooms prolifically– the incarnata has never bloomed. Is it because the site is too dry?

    • says

      Incarnata typically blooms its second year. We grow ours in partial shade and this allows the soil to retain more moisture. If it’s planted in a dry area of your garden, I would try moving it…you’ve got nothing to lose if it hasn’t bloomed for 5 years. Good luck!

  2. Mary says

    I have a few plants of incarnata growing in partial shade and dry sandy soil on the New Jersey shore. It is doing very well, but the blooms do not last very long. We had monarch butterflies, eggs, and caterpillars this year. I just harvested twelve ounces of seeds from 6-8 plants. I also have many tuberosa plants nearby. The blooms last longer and it reblooms more readily when pinched back.

    • says

      Hi Mary, the short bloom period is likely the result of growing in dry, sandy soil. Swamp milkweed likes it wet. Congrats on all your eggs and caterpillars this season, and on your bountiful harvest!

  3. Mke Bryan says

    In Wisconsin we have a place called Prairie Nursery .I bought five plants last summer and planted them by our down spouts to give them extra water. This year I had more insect activity than ever. I’ve had Butterfly Weed for years and have not had much luck attracting Monarchs .That all changed with the Swamp Milkweeds.

    • says

      Hi Mike, glad to hear adding more varieties of milkweed brought more monarchs to your garden. This was a banner year for swamp with cooler temps and more rain in the upper midwest. You’ll find that “favorite” milkweeds change from year to year depending on the weather patterns. There were also more monarchs this season too…I hope this trend continues going forward. Congrats on your swamp success!

  4. Charlene Cornett says

    I’m so glad I found this website. This is my second year raising butterflies and have found this site very informative. I have the perfect moist spot for swamp milkweed. now that I know – that will be my new project.

    I have a large area of common milk weed and hoped to harvest the seed but have lost most to aphids and beetles. Other than hand clean the pods what else could I be doing to save more seed? Black birds do a wonderful job of cleaning when they come in a flock , but you know how they are–here today, gone tomorrow.

    • says

      Hi Charlene, I’m happy to hear you have taken up the hobby of raising monarchs…a fun and rewarding experience. Aphids and beetles can be pests, but I usually try to combat pests by diversifying milkweed varieties and putting several patches throughout the yard and garden.

      If you feel you need to remove beetles, you could always flick them in a bucket of soapy water, which works well for Japanese beetles. Otherwise, I think birds eat them too. Here are 7 ways to get rid of aphids…good luck!

      Stop Aphids from taking Over your Milkweed

  5. Brian says

    Hi Tony,

    We have been butterfly gardening for a few years now, and I just read that swamp milkweed has an average lifespan of 3 to 5 years. We haven’t lost any of our plants yet, but this will be the fourth year for our original swamp milkweed and I wonder if I should start a few new plants from seed this spring just in case we start losing our original plants in the next year or so?

    Have you had to replace any of your swamp milkweed, or have your plants lived longer than the average 3 to 5 year life expectancy.


  6. Sheila Spotswood says

    I saw a mention on another list of features of swamp milkweed that it could grow in a swamp or pond. Do you know if we could actually grow it submerged in a pot in a pond with a plastic liner, no swamp or wetland type edge. Full or maybe filtered late afternoon shade, depending on where we put it. We’re adding more local milkweeds in sunny ground areas, and I love the idea of some pretty pink ones in the pond.

    • says

      Hi Sheila, I haven’t personally grown it in water, but it’s in a section of our yard where there is often standing water after snow melt and after heavy rain. I’ve also seen it growing right next to lakes/ponds where I’m certain it must be submerged during wetter periods. I would try a few and see what happens…please keep us posted!

  7. Mary Reilly says

    I am growing a butterfly garden for a few years now. Last year I planted swamp milkweed asclepias incarnata. I have saved lots of seeds and also threw lots of seeds back in the garden. I am new to this. I want to buy more milkweed different varieties annd plant but no one seems to carry it on Long Island. So where can I buy it? Also what varieties? Last year had lots of problems with aphids . I cut down plants to ground. Will they grow again?

    • says

      Hi Mary,

      if you can’t find any good local resources, check out my resources page for milkweed seeds and plants. The page also lists native regions and perennial zones to give you some ideas:

      25+ Milkweed Ideas for Butterfly Gardens

      Swamp milkweed is pretty resilient so I would be hopeful it will come back this season, even after cutting it back. Good luck!

  8. Holly says

    I like the purplish color of the Swamp Milkweed shown in these pictures. Where can I get seeds that will produce this color of plant? Also, I’m in upstate NY and my Asclepias Tuberosa dies out here in the winter. Other people write as though it lives through the winter. Am I missing something? I grew tuberosa in Santa Monica CA and it lived through winters, along with Monarchs that graced my garden year-round. I’ve been trying to find out which Ascelpias species will live through the winters in upstate NY. Any advice would be appreciated. Thanks!

  9. Tammy Potte says

    I have swamp growing from rhizomes. So if I read these posts correctly, seeds do better in pots and rhizomes do better in the ground. last year we had no luck with the seeds, but this year I bought a rhizome and it just took off.

    • says

      Hi Tammy, swamp milkweed doesn’t have rhizomes…just a regular root system. This makes it an easy milkweed to transplant in your garden or in containers. You can try growing any variety of milkweed in containers. If the variety spreads through rhizomes, you’ll want a bigger pot to accommodate them.

  10. Kat Rugar says

    I bought a swamp milkweed plant last year and planted it in a sunny
    spot in my Richmond, VA garden. To my surprise, it is growing strong
    this spring. Can I divide this plant, or take a cutting, to increase my
    If I can take a cutting, can I use the tropical milkweed instructions?

  11. Barbara Bonforte says

    I’ve been raising monarchs for over ten years…I recently bought swamp milkweed and am wondering if it will grow well and survive a New Jersey winter if I plant it in pots rather than in the ground. A friend told me it would not flower in a pot and that it would not survive the cold of winter. Please advise.

    • says

      Hi Barbara, swamp milkweed will bloom in containers if it’s a second year plant or older. We don’t overwinter swamp in pots, we leave a few seedlings in undesirable places, and then pot them up when they return next spring. You can also keep them in pots. I would advise putting containers in a protected area or wrapping the pots to keep soil temps warmer until spring.

  12. Brian says

    Greetings from the Williamsburg, Virginia area =)
    I have a quick question for you Tony,
    How can I safely separate our swamp milkweed so I can plant it all over my yard? We get plenty of sun and water, so it should be the perfect conditions for it to thrive.
    Right now, there are about 20 stalks on our plant. If breaking them up and spreading them out is gonna threaten its survival, I’ll just keep it together as it is. But I’m hoping I can spread it out & COVER my backyard with it.
    Kudos to Tony and all ye excellent Monarch supporters!!

    • says

      Hi Brian, I’ll be dividing our swamp ‘ice ballet’ cultivar for the first time. For spring, I would do this before it starts putting up stalks, so you are are probably too late for this season. We are going to try this in fall when we typically divide plants…can’t imagine why this wouldn’t work well for swamp milkweed. However, if it’s your only plant, next spring is a sure thing. Have a fantastic season, Tony

  13. Yvette says

    I have a North side area that gets around 6 hours of sunshine and can get very wet when it rains. I live in North Texas. Will swamp milkweed thrive in this area? Dill plant is growing very well.

  14. Diann says

    I planted Butterfly Weed, asclepias incarnata ‘Soulmate’, in my backyard where my dogs will be around it. Do I need to move it? Is it poisonous for them?

    • says

      Hi Diann, it’s potentially poisonous if they consumed a large quantity of it, but most pets won’t touch milkweed as it has a bitter taste. Our dogs have never even nibbled on milkweed and we grow it all over our yard. The only reason I would consider moving is if your dogs have a history of eating garden plants.

  15. David Gilmore says

    I have a “bog filter” where water from my koi pond is biologically cleaned and have had some kind of milkweed there for years. The bog filter is a bed of gravel over a rubber liner and is constantly saturated with water. Having seen a monarch at the plant today, I did some research and it is likely A. incarnata. It must be over 4 years old. It mixes well with the water irises and pickerel weed and being 4 feet tall always stands well above them to get plenty of light.

  16. Amy Kirchoff says

    I live in Richmond, VA and I planted 5 swamp milkweed plants last year. I am beginning to think I planted them too close together because this year they came back much larger than they were last year with more stems coming out of the ground. (Should I cut some of the main stems off?) The soil this year has been wet due to rain. The leaves (esp. bottom ones) turn yellow – I pick these off – some of them have spots on the back. The top leaves are in great shape so far but the plants are very crowded because they are so huge. I also have two new plants whose leaves are not turning yellow. I’d like to propagate some plants from cuttings just in case I need more plants. How do I do that?

    • says

      Hi Amy, you could cut back some stems if the plants are competing for space. I would space out/transplant at the end of the season, so they can flourish in future seasons. You could divide the root to create more plants, and you can also try to take cuttings incarnata:

      Swamp Milkweed Cuttings

  17. Lindsay says

    I have dug up some swamp milkweed from a near by ditch (mowers will get it otherwise). How do I transplant it to my garden? Right now it’s sitting in a bucket of water.

    • says

      Hi Lindsay, swamp milkweed is pretty easy to transplant because it has no taproot. In perfect circumstances you would do this at the beginning or end of the season. I would transplant as quickly as possible, and make sure the soil stays most while the plants acclimate to their new surroundings. If you were going to try a transplant mid season, swamp probably has the best chance of survival…good luck!

  18. Denise says

    Our swamp milkweed bloomed beautifully it’s second year here in NJ. Last year we deadheaded tuberosa and it rebloomed. Can we do the same with incarnata? If so, I might need a stepladder! Thanks.

    • says

      My understanding is that you can deadhead incarnata for a second bloom period, although we have not tried it before since our curassavica blooms prolifically late-season. I am going to try cutting back some incarnata this week too. I will add more info to the page after I see the results…

  19. Maureen says

    I just purchased 4 plants in plastic containers in 1 gallon pots. I am already noticing very small caterpillars who are eating the leaves of my plants. My worry is 3 of the plants have several yellow leaves and its growing up my plant. I have only had these plants for 2 days, I am getting worried. I live in southern CA and its been pretty hot. 85 degrees lately. I currently have them under my patio awning made of wood. The soil seems a little damp but not wet. What can I do to stop my leaves turning yellow? I have Blood flower silky golds & red butterfly weed. Help!!!

    • says

      Hi Maureen, I just remove yellow leaves from plants to let healthy new growth emerge. Sometimes leaves will turn yellow if the plants are overwatered. Tropical and swamp milkweed both typically grow well in partial shade if that’s what your plants are getting…

  20. Joyce Musick says

    I want to plant the pink swamp milkweed in containers for the balcony.
    Where can I buy seeds?
    What is the best materials to use?
    Planter – ceramic, taracota or plastic?
    Soil- regular potting mix or triple mix?
    Stones – required? Bottom, through out or top?

  21. Lori says

    My milkweed is in its third season and the blossoms are enjoyed by lots of pollinators. Monarch’s frequent the plants (four large clumps, mixed in with other butterfly plants, spanning 20 feet) but do not seem to lay their eggs on the plants. Instead, they lay their eggs on Butterfly Weed and we’ve had lots of cats devouring them to nubs. I’ve read that Butterfly Weed is a Monarch’s second choice for laying eggs. Do you have any idea what could be wrong with my milkweed? We’ve had eggs and caterpillars on them in years past. Thanks.

    • says

      Hi Lori, congrats on all your monarch activity! First off, butterfly weed is a type of milkweed:

      Asclepias tuberosa

      Typically, monarchs choose swamp milkweed over butterfly weed but it depends on the time of the season and the conditions of the plants. Do the leaves on your swamp plants look lush and healthy? Which type of milkweed has more predators crawling around? There are many factors that could persuade a monarch to choose one milkweed variety over others. That’s why it’s a good idea to plant several varieties…

  22. Meredydd Francke says

    We live on the east coast of Florida, Zone 9b. I just bought an asclepias perennis at a native plant nursery on Sanibel Island – which is on the east coast. The plant tag says it will thrive down to Zone 8b, so I was wondering if I should give it more shade – the tag says full to part sun – should I plant it in part sun rather than giving it more than that, since we are one zone further south?

    Thank you – what a great website you have.

    • says

      Hi Meredydd, I have not grown A.perennis before, but since it likes moist soil conditions I would definitely try some in partial shade. You might try planting in two different growing conditions and see which it prefers. Then, you can transfer all plants to the best area. good luck!

  23. Dennis says

    I planted three swamp milkweed plants in the early Spring and each had clusters of flowers. Now I must have a total of at least 30 long narrow seed pods! What do I do, just leave them fall to the ground; pluck some off to give to a friend??? I have other plants/flowers in the same smallish area so I am not interested in turning the whole space into a butterfly garden. Thank you.

  24. JUDY KARCHER says

    Hi Tony ,
    I’m planning on starting new Milkweed this fall,after the ground freezes,Going to put them in pots so I’ll have them growing nicely for our garden club plant sale in the spring .
    Do you think if I plant them in pots and put the pots half way in the soil under the sun deck that they would be OK ?
    Released my last Monarch midweek,do you think he will make it to Mexico before the hard freeze ?

    • says

      Hi Judy, you can try it and see if it works. You can also try winter sowing with a mass of seeds and then separate the seedlings in spring. It’s always good to try a couple different propagation techniques in case one doesn’t work out for some reason.

      As for your monarch, if he is strong and healthy, he definitely has a good shot. :)

  25. Sally says

    I live in Los Angeles and just bought 100 packs of ‘Swamp Milkweed” seeds from Save our Monarchs. Will they grow here? I have found contradicting opinions all over the web. We are a mile from the beach, but not really a “swamp”. What do you think?

    • says

      Hi Sally, I know some who have successfully grown it for a season, but I’m not sure if it seeds or comes back vigorously the next season. Incarnata does not have to grow in a swamp, but prefers moist soil. It never hurts to try, but make sure you have tried and true natives/perennials in case it doesn’t. good luck…

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