Gomphocarpus Physocarpus

Giant Swan Plant Milkweed for Monarchs

Gomphocarpus physocarpus common names: Asclepias physocarpa is the former botanical name, Bishop’s balls, Goose plant, Giant swan plant, Hairy balls, Family jewels, Oscar, Cotton-bush, Balloon cotton-bush, Balloon plant milkweed

As the peculiar pods of Balloon Plant Milkweed start to ripen, they'll take on a deep sunburn. The September milkweed leaves remain viable for feeding late-season monarch caterpillars. More Photos, Info & Seeds...

Gomphocarpus Physocarpus Plant Specs

  • Perennial zone for USDA zones 8 and above (lows -12.2 °C or 10 °F)
  • Native range: eastern part of South Africa
  • Fast growing annual for colder zones
  • Full sun to part shade
  • Height: 4 to 6 feet (can grow taller)
  • Spacing: 2 to 3 ft
  • White flowers with purple accents
  • Blooms mid to late summer
  • Not the same plant as its bushier brother swan plant milkweed

Giant Swan Plant Pros

  • Fast growing annual milkweed
  • Can sustain lots of munching monarch caterpillars late season in September and October
  • Nectar source for monarch butterflies
  • Long stems with pods make this ornamental plant an amazing table centerpiece
  • Use long cuttings to feed caterpillars indoors
  • Last viable milkweed species before fall takes over
  • Deer and Rabbit resistant (but they will eat if other food sources scarce)
Balloon Plant Milkweed Flowers are Creamy White with Pretty Purple Highlights. The flowers contrast nicely against dark green milkweed leaves.
White Elegance with a Hint of Purple Passion

Giant Swan Plant Cons

  • Colder hardiness zones must start seeds indoors for hopes of a seed harvest, or overwinter indoors under cfl light bulbs
  • Flowers aren’t super showy, but still pretty
  • Prone to aphids and other insect pests like all milkweed species
  • Fewer pollinators use this compared to native species of milkweed

Gomphocarpus Physocarpus Plant Propagation

  • Start seeds indoors 2 months before final frost
  • Sow seeds directly after final frost (not recommended below zone USDA zone 8)
  • Soak seeds in water 24 hours before planting, no cold stratification
  • Stem Cuttings
  • Start seeds in water
  • In annual zones, starting with plants is the best option to insure plants have time to seed
Asclepias physocarpa (ballon plant) pods
Great Balls of Milkweed!

Giant Swan Plant Growing Tips

By taking stem cuttings of Gomphocarpus physocarpus, you can make a unique centrpiece while also giving milkweed seeds more time to develop indoors. More info and find seeds for your garden...
A Unique Centerpiece + More Time for  Milkweed Seeds!
  • Start seeds indoors 1-2 months before avg last frost
  • Seeds germinate in less than one week with heat and moisture
  • Use an oscillating clip fanir?t=monabuttgard 20&l=ur2&o=1 gomphocarpus physocarpus on seedlings to strengthen the stems to simulate an outdoor breeze…a must for strong stems!
  • Grow this as a back border so it doesn’t shade your other butterfly plants
  • Can be grown in large containers
  • Cut I- you can cut them back late spring for bushier growth
  • Staking may be required if not cut back in perennial zones
  • Cut II- Is fall setting in before seeds are ready to harvest? Take stem cuttings with the largest pods (leave seed pods attached) and place them in water. This should give them the time they need to finish developing.
  • Don’t force open seed pods…they will start to open when they are ready
You'll know balloon plant milkweed seeds are ready to harvest when the seam starts to split, revealing the dark brown seeds inside. If the seeds aren't ripe before your first hard freeze, take a stem cutting from the plant (with the pods attached) and put it in a vase inside. This will give the seeds a couple more weeks to fully develop.
Open Sesame!

Pollinator Plus:

The most frequent visitor I’ve noticed up north is the blue mud dauber (black wasp). Recently, I’ve also noticed monarchs, hummingbirds, and hornets sipping nectar from it. If you have noticed other pollinators on the goose plant, please leave a comment below.

nature note: Though the mud daubers look ominous, they have never shown aggression in our garden. They’re also frequent visitors to our swamp and tropical milkweed plants.

Monarchs use Balloon Plant as both a host plant for caterpillars and nectar plant for adult butterflies.
Hanging from the Petals of Giant Swan Milkweed

Buy Giant Swan Plants and Seeds

Always purchase milkweed seeds and plants by botanical (scientific) name to avoid purchasing the wrong milkweed species:

1. Purchase Gomphocarpus Physocarpus Plants or Seeds from Joyful Butterfly

2. Find More Gomphocarpus Physocarpus Plants and Seeds on Etsy

One more time: starting seeds indoors early will give you a huge jump on the season and is a must for northern gardeners. This milkweed species is a rare find in nurseries, so seeds are probably your only option in most regions.

Click Here to Explore 30 Milkweed Options for your Butterfly Garden

Please read comments below for more info about growing Gomphocarpus physocarpus in your garden:
Share the Joy of Butterflies


  1. The leaves on my hairy balls plant are turning yellow. And I can’t figure out why

    1. Hi Kae, this often has to do with water…too little or not enough. you probably have an idea as to which one. Leaves usually start yellowing toward the base of the plant. Just remove and discard those leaves and adjust your watering habits to see if that makes a difference.

  2. I just saw this in a local nursery next to giant milkweed today. Since I am reading the cats prefer Oscar’s over giant, I am interested in this one – but can it carry OE? I trim back my tropical milkweed annually since I am in central FL (9b) and it is a perennial which can end up carrying OE. Do I need to do the same with Oscar’s? If so what would you recommend in terms of that since it’s woody would you still trim it back to about 6-8″ tall? I have stratified and have sprouted some common milkweed which is local and I will not need to trim, but it is slower growing so won’t do much this summer – and I can’t find that at local nurseries.

    1. Hi Kris, we have seen more eggs on the physocarpus, but this can vary from season to season…they are both used as host plants by monarchs. Yes, this is also a continuous growing species that should be cut back periodically to prevent the spread of OE and other pathogens…

  3. The balls on a couple of my balloon plants have been full-sized for well over a month. They are also turning that reddish color like in the picture at the top of the page, and some of them are starting to feel “papery”. Are they gonna ripen any time soon? Luckily, the ripest ones are on a potted plant that I can bring in, but I was hoping to cut it way back for the winter so it will fit in the house 🙂

    BTW, all kinds of wasps *loved* the flowers. I don’t think I ever saw any other kind of pollinators on them.

    1. Hi Bob, it sounds like your seeds are getting close! If it freezes before they open, you can always take a stem cutting to put in water and let it finish indoors…guessing it won’t come to that. Yes, wasps are the main pollinators for the Gomphocarpus species…

      1. I dragged the potted plant indoors Thursday night for the freeze, and took cuttings from the big one in the vegetable garden to ripen the seeds indoors. The first pod (on the potted plant) just split today, with lots of shiny dark brown seeds inside. Several more should be opening any day now.

        The seeds are smaller than I remember! Are they a lot smaller than common milkweed and swamp milkweed seeds? (kinda looks like it in your “open sesame” picture)

    2. I’m in Zone 9B- nursery plant grew well over 6 feet- allowed pods to disperse seeds and also harvested seeds for 2018 season.
      Attracted so many Monarch butterfly’ caterpillars- hatched 25 even during Hurricane Irma and let them fly. Not as many aphids as other varieties of milkweed, did notice an increase in Lady Bugs as a result.
      Very interesting plant- now a monarch hatchery, use cuttings to allow them munch, pulpate, transition into monarchs.
      Very easy… try it out

  4. Hi. I’ve planted balloons in a pot and hope they will do well, growing through the Utah winter. Any tips on it’s desired soil moisture or other? Thanks.

  5. Hey there.. I’m outside of Vancouver, Canada. I have over 20 of them growing in my yard. Most all of them are 6+ feet tall and filled with large maturing seed pods. It’s a party of pollinators out there.. everything from honey bees, bumble bees, butterflies, wasps, drone flies and even a hummingbird.
    I’m curious if any will survive the winter, but either way I’ll start seeds indoors again in the spring.

  6. I have a six foot Oscar that I grew from seed started indoors, zone 7 (WV). It has attracted a lot of pollinators including the Monarch and several other butterfly species, bees, wasps, hummingbird moth and hummingbirds. Everyone is curious about this interesting plant and have asked for seeds, which I will gladly share as it is a wonderful way to increase awareness of the. Monarch’s plight. Thanks for the tip on pruning late spring for a bushier plant as I did have to tie it up a couple of times! Happy gardening everyone!

  7. I have 2 balloon trees that had tons of balloons. They are all dry now, but the branches are dry too, as if they are dying. Is this the normal lifespan—tree dies after “ballooning”? We have been watering plenty—so I don’t think we killed them by under watering. We do have a lot of those red and black bugs on the trees—maybe they killed the trees? Maybe the trees are not dead and we just need to trim them all the way back to the trunk? Any advice is much appreciated. Thx!

    I forgot to mention that I live in Long Beach, CA. Zone 10b : 35 to 40 (F). we planted these as 4 ft trees about 11 months ago—they are now about 5.5 feet tall.

    1. Hi Paul, I’m not sure about the growth cycle in warm regions on the US. We grow them annually in zone 5. They are cold hardy to zone 8 so if you’re in a zone 8 or above, it should hopefully come back next season, but I would ask someone who grows this in your region. Try a facebook group like:

      Building a Butterfly Garden

      PS…milkweed bugs eat the seeds, but don’t typically kill plants

      1. Thanks for the info. I’ll try trimming it and see what comes back. Only thing is, I don’t know how to properly cut them back. Should I cut every branch back to the trunk—and end up with a stick of a tree? Or do I have this all wrong? Help!…please.

        1. trim back but leave a couple of growing bubs on each stem the way you want the plant to grow. trim height as well.

  8. I received some seeds and grew about 8 plants in a large pot in southwestern Ohio—monarchs laid tons of eggs on them in August, and I had several hummingbirds nectaring often on the blooms in the early morning.

  9. Until one particularly large swamp milkweed plant started producing flower buds, these were the plants where we found the most eggs. The mama Monarchs seek them out. Now they seem to prefer the swamp MW flower clusters. (I was hoping that plant would actually get to bloom this year) We’re still finding a few eggs on the physocarpus seedlings (about 2 feet tall now) too.

    1. I have a tall plant …had the flowers and still have a few but…don’t see any pods coming….

  10. How well do G Physocarpus do in the garden in our short but very-long-day Minnesota summers? I have a dozen or so plants in 4.5″ geranium pots, and a few in 6″ pots, and a few still in little Dixie cups that I’m moving up to bigger pots today. Just wondering about setting a few out in the flower beds since its a hot day.

    The little monarch caterpillars seem to like it. I will have to rescue the plants from them in about a week. 🙂

    1. Hi Bob, they grow well here but it’s best to get an early start so they have time to seed. Ours have thrived when planted directly, but not so much in containers. Good luck with your plants!

  11. I just found the packet of G. physocarpus seeds that I bought a year ago and I planted them. Since the seeds are over a year old and they are tropical I planted the whole packet. They are in moist potting soil in half a milk carton, under 220W of fluorescent lights and wrapped in saran wrap so they don’t dry out. (you should see my stocky little pepper plants under these new lights)

    This is a tropical variety and my seeds are old, so should I expect 0% germination and order another packet of seeds real quick? Or will they last a few years like temperate-climate varieties? The packet said 25 seeds but it looked like more than that. All I really need is a couple of plants.

    How quickly do they germinate? The seeds were a lot smaller than native milkweeds, so I didn’t want to pre-germinate them in wet toilet paper.

    1. Hi Bob, year old seeds should still be fresh. I would expect a high germination rate. Typically G. physocarpus is one of the fast species to germinate, starting in under a week. I typically soak the seeds in water for 24 hours before planting to soften the seed coat. I started some in our porch last spring and was successful (I’m in Minnesota) You can see the results of G. fruticosus, but this also worked for the balloon plant:

      Starting G. fruticosus seeds in a wet coffee filter

      1. That’s good to hear. I will start checking them in a day or two so I can remove the saran wrap. If I end up with 40 or 50 plants I can give some away.

        I’ve started using toilet paper instead of paper towels to germinate seeds on, because I have had tomatoes seeds send roots into the paper towel and be impossible to get them loose w/o breaking most of them off (I threw those seeds away and started another packet.) The TP just falls apart when it gets wet. So far it’s working pretty well. I bet coffee filters are good too ’cause the roots probably can’t grow into them.

        The common milkweeds that I just took out of the fridge Saturday are germinating already. I’ll have to plant them tomorrow. Wife wants large common milkweed plants in nursery pots to grow caterpillars on this year so I’m getting an early start. That’s also why I’m planting the G. Physocarpus; it should be able to grow faster than they can eat it — first year A. syriaca might not be able to stay ahead of them.

        1. they would still grow even with the paper towel on the roots but I get that problem too.

        1. Ok to use tap water? Not much rain water in Texas right now. What about bottled spring water? Or??

          1. but stand the tap water for an hour as this release’s any chemicals in the water.

  12. I live in South East Michigan. I was able to find the hairy balls milkweed at a local native nursery last summer and it did really well in my garden. I had over a dozen eggs laid on it! The only thing I saw enjoying the nectar was a lot of ants! The pods did not mature in time before the cold came, even tho we had a loooong warm fall. But I was able to cut the stems and have had them in water inside and now the pods are finally opening. My question is, given my locale, when is a good time to start the seeds inside? I really want to have a few of these plant this coming season. I’m also adding showy,whorled, and common milkweed to the butterfly, tropical, and swamp milkweed I already have. Also, when is a good time to start the tropical seeds I gathered from last season’s plants? Do those need cold stratification too?
    Thanks and happy New years!

    1. Hi Matt, I would start them about 2 months before direct planting. You can start them indoors or try spring sowing seeds. Winter sowing temps are too cold, but if you wait until March to prepare sowing containers for warm weather varieties, you should have good germination rates…good luck!

      Spring Sowing Milkweed

  13. This past year I planted two species of Gomphocarpus in my garden in northern California (Zone 9): Gomphocarpus physocarpus and G. cancellatus. Both plants are doing well in dry garden conditions, but I have not had any monarch caterpillars on them so far. My garden’s last monarch cats were about five years ago on Asclepias curassavica plants, that later died off in a cold winter.

    Gomphocarpus cancellatus is becoming a more commonly grown species in my area. I am interested in learning more about it’s suitability as a larval host plant for monarchs.

    …and yes, I am also interested in growing native milkweeds in my garden but have not had any success so far with A. fascicularis, I intend to try again with A. speciosa next spring.

    1. Hi Marck, native is important for creating & maintaining a healthy ecosystem, but non-natives can also be beneficial for monarchs and other garden visitors. There’s no reason you can’t have both, in my opinion…good luck with all your milkweed!

      1. The reason you shouldnt mix natives and non natives that are this closely related is that they will hybridize and you’ll lose native population

        1. Hi Adam, I have never seen or heard of gomphocarpus species hybridizing with asclepias species…for that matter, I have yet to even see asclepias hybrids, and we have 17 species of milkweed in our garden.

          1. You are right. I was told my A. incarnate would hybridize with A. perennes but that has never been the case for years.

  14. Thank you for writing about this plant. I was given a bouquet which included it a few weeks ago. The seedpods have opened, & now that I’ve ID’d it, I’ll be saving the seed to grow along with my other milkweeds next year.

  15. I have milkweed plants and hairy balls milkweed. I am saving some seeds from the milkweed. Do I now just remove plants from garden as I assume neither plant will come back next year. Ohio, Marilyn

  16. Hello!
    I live in Michigan and purchased several stems of this plant at a local market. I would like to harvest the seeds to start indoors early spring. Should I dry the stems and “balls” or leave them in water and give them an occasional fresh cutting until they open?

    1. I would leave them outside to develop until just before your first frost. Thank you can cut the stems and let them finish developing indoors…good luck!

  17. I was wondering if these can be dried and used in dry flower arrangements.

    1. hi Debra, I’ve brought in stalks with pods to develop the seeds more and can confirm they would make a great flower arrangement. I know some florists use them in actual flower arrangements too.

  18. Germinating the seeds in water gave me a lot of Gomphocarpus physocarpus plants this year. The flowers are being pollinated by honeybees, several other bees and wasps and by monarch butterflies. I’ve been using cuttings for raising caterpillars indoors, but I haven’t been finding eggs and caterpillars on the plants in the garden, except for one caterpillar. We do have lots of common milkweed, and that’s where almost all the eggs have been so far.

    1. Hi Mary, we don’t get many eggs on physocarpus, but have found more on G. fruticosus. I have never seen a monarch take nectar from either species so surprised by your report!

      We have gotten a majority of our eggs on common this year too. As for finding less eggs, those predators are relentless in August. If you don’t find the eggs right away, a hungry predator will.

      1. I found a several dozen eggs on my Gomphocarpus physocarpus this year. I didn’t see any Monarchs at the flowers, but they did leave their eggs.

    2. Great plants that attract monarchs, however be very careful when cutting or trimming. I got some milkweed ssp in my my eye and it almost blinded me. Had to go to the ER.

      1. Hi Mike, milkweed sap from all species can cause serious problems if rubbed in your eyes, so always wash hands after handling. Glad to hear you are ok!

  19. I live in Vallejo , just east of san Francisco . I bought a plant last year , $9.95 in a 6 inch pot and about 4 1/2 feet tall .. it had 9 well developed balls . I collected seeds using a baggie to place balls in before they opened . 1st ones opened , and blew in the wind before I realized it .,After i just left it alone , in the same pot , did nothing . this summer I have 3 small balls starting , but , 50 to 70 buds and flowers blooming…. I was lucky enough to buy it at a tourist attraction , the Filoli estates in Mt. View …. only bought it because strangest looking balls in your face . I guess it loves SF bay area weather

  20. I just bought this milkweed started from a cutting based on the description that it is one of the “most popular” with Monarchs. It came in a 4″ pot and is about the same height. Now I’m reading how sensitive to cooler climates it is. I live Northern California (San Fran Bay Area) Zone 9. I’m sure it won’t bloom this year- we’re mid-way through summer, but my concern is will it have enough time to grow a strong enough root system before frost comes (December.) Any recommendations? Do I cut it down completely and mulch heavily?
    Thank you for your website. I frequent it often for the useful info on plants and butterflies. This is my second year of dedicating my flower beds to the butterflies and I’ve had much success, including seeing several monarch catterpillars.

    1. Hi Steve, you can try mulching and see if it comes back, but it’s a risk. You could always try and get some seeds as back up. It’s a fast growing milkweed and we grow it annually in zone 5. good luck!

    2. I didn’t even bother to cut it back …. and I live near you

  21. Hi! I’m actually looking for these to use in a flower arrangement. I live in Florida. What is the “season” for the pods? Any suggestions where I might be able to find them stateside? I’ve been looking at floral wholesalers, but not having any luck finding any….Thanks!!

    1. Hi Elaina, your best bet is probably finding a local nursery that sells butterfly plants…good luck!

  22. I purchased a hairyball milkweed and how its seed pods are starting to open. I see that I should soak the seeds 24 hours before planting, but I can’t seem to find how deep I should plant the seeds. Do the need light to germinate or should they be covered. I live in Florida zone 10, but I was also wondering if I should start them in pots, because our soil is very sandy.

    Thank you for your info.

    1. Hi Sharon, I would find another gardener/nursery with first hand growing experience in your region to see what has worked well for them. My advice though, is to try BOTH methods and see if one outperforms the other. I always cover milkweed seeds with a little dirt when direct planting:

      Planting Milkweed Seeds

  23. I have recently discovered the Gomphocarpus physocarpus plant on Ebay and purchased some seeds. The seeds were planted indoors and sprouted very quickly. The plants grew approx. 3″-4″ and stayed that way for a few weeks, but, started dying off. I only have about 3 plants left and they are now in a grow pot outside, however, they do not seem to be growing very fast, if at all over the past few weeks. Can anyone give any suggestions on what to do or what I am doing wrong? Do I need to add, or avoid, any Miracle Grow type products? Any help is appreciated.

    1. Hi Martin, if you’re past you’re last avg frost date, you could try transplanting them into the garden. Milkweed responds well to fertilizers, but is not a necessity. These are some of the fertilizers we’ve used over the years. I like slow release because you don’t have to keep applying it:

      Butterfly Garden Fertilizers

  24. I stumbled across this article whilst researching weeds that grow on my property in northern New South Wales, Australia. The main purpose of this comment is to urge caution around Gomphocarpus physocarpus, it is a voracious weed in this part of the world and has become an increasing problem on farmland, roadsides and in conservation areas. It is poisonous to stock and humans and the sap is a skin irritant, I’ve been hand-pulling plants this morning and now my hands tingle and eyes burn (hence my research!). I have noted that many plants have caterpillars on them when removing them, so I guess that’s why it’s of interest here… Anyway, proceed with caution!

    1. Hi Craig, thanks for posting. In most regions of the US physocarpus is an annual. Most milkweed species have sap that is an eye irritant, so always wash your hands after handling. There have been instances where people have had to go to the emergency room so I would suggest seeing a doctor if your eyes are still bothering you.

  25. I have had a huge issue with Aphids. I’m trying to look for a natural way to fight them. I have used probably 500 ladybugs and about 100 lacewings and they hardly dented the problem. I ended up using neem oil and that works but don’t know the damage to caterpillars from the oil. Do you have any suggestions.

    From northern california

    1. Hi Derek, aphids are the bane of butterfly gardeners across the country, so I’ve compiled a list over the past few years on how to combat them. We haven’t had an infestation in our northern garden since 2011, and over time we’ve seen more aphid predators as our ecosystem has developed naturally. It’s a good idea to expand your selection of milkweed varieties and have several patches around your yard and garden. That way, there is usually some that will be aphid-free. Here are some ideas that can yield instant results:

      How to stop Aphids from taking over Milkweed

  26. Hi,
    I live in Los Angeles and my neighbors milkweed, hairy balls, are starting to seed. I collected some of the seeds from the pods that have opened. When & how do I plant the seeds?
    Thank you,

    1. Hi Mary, if you’re in California you can plant them directly outdoors now or in spring. If you want the G. physocarpus seeds to germinate faster, soak them in water for 24 hours before planting. good luck!

      planting milkweed seeds

  27. I am in Zone 7b – Burlington, NC. Should I go ahead and sow mine now or wait til spring?
    Thank you

  28. I have balloon plants reseeding all over a large lot in Oakland, CA and am giving away the seedlings. Two questions: When should I look for eggs since the plants go strong year-round? Should I let the lady bugs and aphids duke it out or spray the plant with a hose to remove the aphids?

  29. I ran out of milkweed in Sept., 2015 and bought some which I think had been treated because I lost a lot of cats. My question is: I am rooting in water a bunch of the stems I cut to use. Are these cuttings from the parent plant contaminated? Most of the cuttings have a lot of apids. Does that mean I can use for eggs and cats next summer?

    1. Hi Margaret, typically pesticides can last from weeks to even months depending on what type was used and how much. I would guess it would be fine to take cuttings to start new plants, but again, it’s hard to say without having all the details. good luck!

  30. Hi, I am in North Carolina, Zone 7b. Will this plant grow here as a perennial? Or would I have to bring it in to overwinter?
    Thanks a lot

    1. Hi Fran, you’re on the borderline for hardiness. If you leaf mulch the plants before winter they might come back. Otherwise, you could overwinter indoors or start seeds indoors next spring.

  31. Hummingbirds have been pollinating my Gomphocarpus physocarpus. The Great Black Wasps have probably been there too, but I’ve only seen those on the tropical milkweed. I’ll have to bring the plant inside when the weather turns cold, but I’m hoping that the seedpods will continue developing under lights.

    1. Update: the Gomphocarpus is inside now, and the seedpods are continuing to enlarge. They were less than half an inch across when the plant came indoors, but they are more than an inch in diameter now.

  32. Hi Tony
    I have been given some of the seedlings and hope they do ok over here in the UK . I live in the sunnier south east, will they be ok overwinter?? do they need to come indoors??? Thanks Linda

    1. Hi Linda, please check out the zone info on the page to see if it is winter hardy in your region. If it’s not, you would need to overwinter the plants indoors or start seeds indoors early next spring. good luck!

  33. I have got a balloon milkweed, but I don’t know what the benefits of this plant are and what it’s used for?

    1. Hi Khaba, the ballon plant is a host plant for monarch butterflies (Danaus plexippus) and also the plain tiger butterfly (Danaus chrysippus)…

  34. As soon as we planted the balloon plant, the butterflies immediately went to it and planted their eggs. The birds kept eating the caterpillars so I put a wire fence around & on top of it so that the butterflies could still get in but the birds can’t. I don’t understand why some of the caterpillars are falling off and walking away from the plant now. I went from, at one point, having 11 to now having 4. We also bought 2 of the Tropical Milkweed and the butterlies are ignoring those.

    1. Hi Rhonda, if you just purchased the plants, they might have been treated with pesticides or they could have OE spores or bacteria that are making the caterpillars sick. If possible, it’s always best to have a healthy supply of milkweed (home grown) before raising monarchs.

      If the plants were treated with pesticides, I would suggest cutting them back so that healthy new grow can emerge. If pesticides weren’t used, you could always try raising a few indoors on stem cuttings after thoroughly rinsing the milkweed…good luck!

  35. Has anyone had an itching/burning sensation on arms after working with Asclepias physocarpa? I was recently smashing and rinsing aphids from my plant and when finished, about 15 minutes later, had a very unpleasant burning/itching sensation on my arms?

    1. Hi Chris, I’ve never heard of this happening to others handling physocarpus. Perhaps you were exposed to more sap because of your aphid removal technique? Maybe it was was an allergic reaction? If it happens again, I would wear gloves when handling the plants.

    2. Hello Chris… As Tony said in his response, you probably made contact with the milky substance from the plants. Take this as a warning… You might be extremely sensitive to the plants, so it would be best to wear long sleeves/pants & gloves anytime you work around & in your Milkweed!
      Also… DO NOT LET ANY OF THE MILKY SUBSTANCE GET INTO YOUR EYES!! I have been there, done that, & it isn’t a fun experience, let me tell you!! Even though I flooded my eye with water for multiple times, several minutes each time, I still had to go to a Emergency Clinic, which put me thru another serious eye rinse process… they gave me some kind of pain killing eye drops when I first got there, which eased the burning & tricked me into believing that I was thru the worst of it, but, within a few hours, the horrific burning came back, & my eyes had become so sensitive to light that I sat in a dark room with dark sunglasses on & even the dimmest of lights felt like a dagger in my eye! I had a miserable night & was taken to an eye specialist in the morning, that determined I had torn a hole in my cornea! I was lucky, though, as my eye has healed up without having any long term complications that I could of had! My friends & neighbors all thought that I would stop growing Milkweed because of my ordeal, but, not a chance!! I love the butterflies too much to do that! I do have more appreciation for my eyesight, though, & I will be a lot more careful any time I handle Milkweed… and I warn everyone I share the plants with, to do the same! And now, I am warning you, as well as any one that should read this, to do the same!

  36. Caterpillars stripped my tall tree that I bought, then it died from lack of water–(I had a baby and no one tended the plants for a few days). I was able to germinate several seeds though. They grew to about two inches high, then lost their leaves several months ago. All of the stems are still green and alive months later, but no leaves. I am totally confused! Has anyone else ever had this experience? I am in Florida, so they have been outside most of the time, aside from a couple when I brought all my plants in in to let the potted tropical mw grow back and to keep butterflies from laying eggs on and eating my seedlings. (The swarms of monarchs I had a few months ago seem to be gone for now. )

    1. Congratulations Mama!

      you did not say where you are in Florida? Perhaps the plants go dormant over your Florida winter? You might want to talk to someone in your region who grows this or a local nursery to get some “Florida” insight. Keep us posted on your plants…

  37. Hi Shirley, you are probably correct about the rooting issue relating to cool water temperatures. I’m sure if you try rooting some in late summer you’ll have better results. Physocarpus should probably grow well as a perennial in your region. If the monarchs used it at all during the fall, you might want to cut back some stems so fresh growth can emerge, the same as you would do for tropical milkweed. Good luck with your new plants…

  38. Hi, Tony. I bought one of the “Goose plants” (it was labeled “Family Jewels”) thru mail order last October, & I immediately planted it outside. (Houston, Texas, zone 9a) It liked the weather & jumped in size, so I started taking cuttings. The first cutting rooted quickly (I passed it on), but after that, rooting them wasn’t so easy. I have had about a half dozen clippings, & I have only managed to get 1 more to root. After reading that they need “warm” water, I’m guessing that may be the problem. I think, if I do this next fall, I will use a heat pad! I am so looking forward to seeing how this interesting Milkweed is going to do! (I have been covering my plant during the “freezes” so that it will be ready for spring migration!)

    1. Hi Shirley,

      I too live in Houston. I want to try raising a variety of milkweed but would be concerned about not cutting back before the spring migration. These plants can hold the O.E. Virus carried by infected Monarchs. If the plants are not cut back, the incoming Monarchs can rub up against or eat leaves with the virus left by last seasons virus carriers. As I am wanting to purchase other kinds of milkweed, could you tell me from where you buy yours?

      1. Hello, Anna. Please forgive me for not responding before now…I somehow must have overlooked the notification in my emails!
        To answer your question about where I purchase my Asclepias plants… Have you heard of Zone 9 Tropicals, in Houston? I have purchased from there, as well as Nelson’s Water Gardens, in Katy, TX. I have been mail ordering from Annie’s Annuals and Perennials in CA. The only drawback from Annie’s, is that they have to spray them before shipping & you must keep them away from butterflies, caterpillars… any pollinators, for a minimum of 3 months. Other than that, Annie’s always ships healthy plants & they arrive in great condition! Their customer service is great, and they have a good selection of Milkweed,too! I have ordered 4 different ones… Davis, Virginia Silk, Wild Cotton, Family Jewels & Thin Leaf Milkweed. My Wild Cotton & Family Jewels have survived, & both have had eggs & caterpillars this summer. My luck with the Davis, Virginia Silk & Thin Leaf Milkweed, has not been as good, but I haven’t given up, yet. Maybe I will get them to survive next summer!
        I want to comment on your concern about protecting the butterflies/caterpillars from the virus that Asclepias can carry. I, too, am very aware of it, & I will cut off a branch(es) from my Milkweed, if I don’t think it looks healthy, any time of the year! I also trim ALL of my Milkweed down to 6 to 8 inches in the fall, although I stagger trimming them, by areas, so that I don’t strip all the leaves away at the same time, just in case there might be eggs/caterpillars that will need food! Last winter I had caterpillars into December & chrysalis’s that hatched throughout our winter! And, because I cut my plants down in the fall, I had healthy, full plants for the spring migration! (I do protect many of my plants from freezes, too. I use buckets, flower pots, even trash cans to cover plants, & I always remove the covers after the freeze threat passes!)
        It is very important to cut the plants down so that they can restart & be fresh, but you don’t have to wait until the spring!
        Good luck with your plants! Maybe someday I will run into you at Nelson’s Water Gardens or Zone 9 Tropicals!

  39. Hi Tony
    Asclepia’s are very good at deterring moles. A few stems with leaves in a mole hole will have them scampering away – possibly to the neighbors garden. 🙂
    I’m not sure if the plant gives off a scent/pheromone or if it is the milky sap – but it works. Planting the plant does not deter the moles – so the deterrent does not come from the roots.

  40. Hi Tony, I noticed this AM that I had at least 10 cats on my Scarlett MW and very few leaves left on my 5 plants so I rushed to the nursery and bought 2 more plants, but while there they showed me several physocarpa that look really good but I hesitated. Meanwhile wasps are killing my cats so I brought my 2 new plants inside and picked 12 cats off outside and brought them in!!

    My big question is, will the physocarpa do OK here? I am in zone 9B or 10A, depends on what chart you look at.
    If so are they a good companion with the Scarlett?
    Or should I get another species? My ground is very sandy and usually pretty dry! Thanks and MERRY CHRISTMAS!!

    1. Hi Toni, I wrote an article about this issue a year ago, and no new info has come to light since I wrote it. I’ve grown tropical milkweed for 6 years now, and have nothing but good things to say about how it has attracted and supported monarchs in our home and garden…there are also simple solutions to the potential problems associated with this species:

      Is Tropical Milkweed Killing Monarch Butterflies?

  41. Just bought from local farmers stand . SE PA USA. Farmer said they spread by seed for her. We also had very cold winter but with heavy snow cover.

    1. Hi Wendy, I think most milkweed seeds can survive cold temps but there is typically much less seeding from warm weather varieties. We even have some tropical milkweed that reseeds in Minnesota. Physocarpa overwinters pretty easily. Good luck with your plants!

  42. Hi Tony,

    A friend of mine just cleaned out his garden and told me that he was going to give me some milkweed seeds. Little did I know that he would be handing me three seed pods the size of small oranges. None of the seed pods are open, and by the time I got home to research what type of milkweed seeds he gave me, it was to late to grab a stem cutting.

    Do you think I should keep the seed pods and hope that they will finish developing, or are they doomed since they are no longer on the plant (or stem cutting).


    1. Hi Brian, they aren’t going to develop further if they have been removed from the stem. If the pods are purplish, you may be in luck and get some mature seeds, but if the pods are green the seeds will likely be white and not viable. My last seed pod finally finished developing. The seeds take a LONG time to ripen. Good luck!

  43. Thanks Tony for sending this link to me through The Beautiful Monarch! Very great information you have here as always. I have never seen such an interesting seed pod before. I tried to open one and found a green pod inside. How long will it take for the pods to be ripe? How do I avoid the fluff blowing all around in my condo if they pop?

    Thanks bunches,

    1. Hi Sherri, don’t worry about physocarpa popping. They open very gradually. When you notice a seam starting to open on the pod the seeds are ready to remove. Don’t remove them before, or they may not be viable.

  44. Right now in Lake Forest, California Green Thumb International has these plants in one gallon sizes with balls and all!

    This is the first year I have ever seen them here and I have been raising Monarchs for 9 years now.

    I am now the proud owner of 3 of these plants. I love them!!

    1. Nice fine DeeDee! I pulled out all our plants today but did make a table centerpiece with a few of the stalks to get more seeds in the next couple weeks. Enjoy the rest of your garden/raising season in California!

  45. Yesterday I was given one of the balls with seeds. Today it popped open emitting the seeds. I live in zone 9b in Southern California. Should I start them indoors too and overwinter them inside or can I plant them directly in the ground? If starting them indoors how many seeds should I put in a pot? What size pot do you recommend? Fertilizer in the pot? Thanks for any help.

    1. Hi Darlene, physocarpa is cold hardy to your region so there is no need to extend the growing season by starting indoors. I would still soak the seeds before planting, but direct planting should work well for you.

  46. This is the first year I’ve planted the hairy balls variety and I love it. I’ve seen a Monarch caterpillar eating leaves and black wasps pollinating. Also, I snapped some pictures of a golden digger wasp visiting the flowers in August. I love in illinois and I’m hoping to save the seeds to plant next year. Thanks for the info on your site!

    1. You are welcome Kerry! If some of the pods are “close” to developing right before your first frost, take a long cutting and put it in a vase. You’ll have an interesting centerpiece and the seeds should ripen to maturity.

  47. I’m wondering whats its use. Is it any useful or it is just a show-piece?

    1. Hi Sunila, while it does make an interesting showpiece in the garden, or cut for a vase, our main use for it is to attract monarch butterflies to lay their eggs on it.

      1. What I’ve learned about this is that, native milkweed makes the caterpillars toxic to birds. The gomphocarpus and other exotic milkweeds do not have this effect. So while I had 17-20 Monarch caterpillars on my plants, they were almost all plucked off by the birds! Food for thought…

        1. Hi Susan, the gomphocarpus varieties and tropical milkweed have higher cardenolide levels than any of the native milkweeds.

          No matter which varieties you plant (both native and non-native), many predators have adapted to the poisonous nature of milkweed, which is why it’s estimated only between 1-5% of monarchs survive to become butterflies outdoors.

  48. I germinated from seed last summer and they grew several feet but never flowered. I live in Maryland in Zone 7. I didn’t plant any this summer but have a nice patch of them growing again this summer in the same place they grew last year. They must be growing from last summer’s roots?

    Have you ever heard of them growing perennially in Zone 7? We had a very cold winter last year as well.

    1. Hi Scott, if you want them to flower and seed in your zone, try starting them indoors 2 months early OR overwinter plants and start cuttings. They are not cold hardy to your zone so I’d be surprised if they came back, but gardening is full of mysteries and miracles so it’s definitely possible. If they did, it didn’t give you much of a head start. We overwintered 4 in Minnesota and they are already forming pods.

  49. Hi Tony

    Some time ago, you mentioned you were going to try propagating Oscar from leaf cuttings. Did you have any success with that? If so, how did you do it?


    1. Hi Dana, I was not able to root physocarpus in water, but I am still going to try planting cuttings in soil (with rooting hormone) at the end of the season. I will be sure to update the page with my results.

  50. I bought several plants of this species last year, 2013, and enjoyed growing it. It made a small annual tree, of sorts, behind a back flower bed. The butterflies loved it, looked great in floral arrangements and I had a lot of fun with the name. I didn’t buy it again this year as it is not available locally. I had bought it 3 hours north of where I live. I wondered if any seedlings would come up as the seeds in the cotton like fluff blew all over the neighbor. Just yesterday I noted a “weed”. I started to pull it and then thought better. I thought I’d give it awhile and see what would happen. I’d forgotten all about the hairy ball plant. Then…it came to me…”great balls of fire…that’s the hairy ball plant!”. The seedlings are 4″ tall. I have 100 days before the next freeze…hopefully that will be enough time to see the plant in all its glory.

    1. Hi Judy, congrats on your physocarpa seedlings! They probably won’t mature this season but you can overwinter them indoors and start with some plants next season. I brought in four last fall.

  51. By the way – they call G. physocarpus Bishop’s Balls in the UK and you can buy seeds and plants there. They sometimes get Danaus plexippus in the UK and a few people raise them.

    It grows so big here in NZ that I call it a “testicle tree”.

    1. Hi Jacqui, thanks for the UK info and the scandalous new nickname. I tried to overwinter one so I could get a ‘tree-sized’ plant this season, but the plant died mid-winter. Maybe next year? I hope all is well in NZ!

    2. Brenda Naylor I bought 8 of the balloon plants at a nursery were I live in central Florida.Iknew nothing about them accept they were milkweed for monarch then I saw the balls come out and went on the site.Will Ineed to start seeds in doors?

      1. Hi Brenda, in northern regions seeds need to be started early or the seed pods won’t mature. You can sow yours directly in Florida…

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