Asclepias Curassavica

Tropical Milkweed for Monarch Caterpillars…
and Butterflies!

Asclepias curassavica: Tropical milkweed, Mexican milkweed, Scarlet milkweed, Bloodflower, Swallow-wort, Silkweed

Tropical Milkweed for monarch caterpillars and butterflies
Tropical Beauty

Plant Specs:

  • Perennial: USDA hardiness zones 8a-11 (lows -12.2 °C or 10 °F)
  • Annual for zones below 8a
  • Full sun to part shade
  • Height: 2 to 3 feet
  • Spacing: 1 to 2 ft
  • Flowers: red and yellow, ‘silky gold’
Monarch Female Laying Eggs on Silky Gold Tropical Milkweed
Baby Bump

Pros:

  • Top plant for monarch egg laying
  • Monarch butterflies and others use as a nectar source
  • A favorite source of nectar fuel for the monarch migration
  • Showy red and yellow blossoms all summer
  • Seeding is not an issue in annual zones
  • Easy to transplant
  • Deer and rabbit resistant
  • Can Still flower while it produces seed- Blooms all season
Asclepias curassavica Buds, Flowers, and Seedpods growing at the same time.
The Multitasking Milkweed…Blooms While Seeding!

Cons:

  • In northern zones, must start seeds indoors to reach full maturity
  • The flowers also attract wasps but they haven’t been aggressive
  • Aphids can be bothersome

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 warm water 24 hours before planting
  • Stem cuttings- easily root in water

Tropical Growing Tips:

  • Start cuttings or buy plants for full season bloom period
  • Lusher leaves in partial shade.
  • Taking cuttings at season’s end to place in water overwinter
  • Collect seed pods as they start to crack open
  • Plants can be overwintered indoors
  • Southern California, Florida and Texas gardeners should consider cutting back tropical plants to the ground in fall to cut down the spread of OE and to encourage the monarchs to finish their fall migration.
Eastern Tiger Swallowtail Tropical Milkweed
Tropical Tiger

Pollinator Plus:

This milkweed also attracts eastern tiger swallowtailsgiant swallowtails, hummingbirds, painted ladies, pipevine swallowtails, queens, wasps, and more…(If you know other pollinators tropical milkweed attracts, please comment below.)

Resources:

1.

 

Click here for 18+ Milkweed Ideas for your Butterfly Garden

Please post below if you have any questions, comments, or suggestions for growing Asclepias curassavica in your garden:
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Comments

  1. Sarah Black says

    I am wondering when you usually do your cuttings of the milkweed. I have plans to create an enclosed butterfly pavillion and a butterfly garden.

    • says

      Hi Sarah, if you want mature tropical milkweed at the beginning of next spring, I would suggest fall cuttings. If you bring plants indoors to overwinter, you can take cuttings a couple months before your average last frost. This gives you a huge head start on the season. I will be posting about fall cuttings in late August or September. Good luck with your new garden and pavilion, Tony

  2. says

    Tony,
    Nice butterfly pictures and we should also be getting our first freeze as well during same time as you. Received some A. Curassavica seeds and have 3 seedlings coming undergrowth light in the basement so excited, each day its seems one more pops up planted 15 seeds and using my tiny warmer as well. Also have seeds of A. Purpurasens and Asperula know both need cold/moist stratification. Would it be beneficial if they had some additional time in a cool fridge without the moist stratification prior to giving them moist stratification? Thanks for all you insights. Brian

    • says

      Hi Brian,

      I’m not sure that starting perennial seeds indoors at this point is a good idea. Tropical milkweed can be started now because it doesn’t have a specific bloom period and you’ll have mature flowering plants the entire summer.

      Purpurascens and Asperula have bloom periods and I’m not sure how growing them all winter would affect that. You would be better off starting those seeds about 2 months before your average final frost in late winter. You could also winter sow them by planting them directly or keeping them in containers outside:

      http://faq.gardenweb.com/faq/lists/wtrsow/2002050141031613.html

      As for cold stratification, all I have ever done is put seeds in the refrigerator for a few weeks. I leave them in their packaging and put them inside a plastic bag in case something were to leak. This has always given me great germination results for milkweed. Hope this helps…

  3. x says

    > “If you know other pollinators tropical milkweed attracts, please comment”

    Bees, of course. Zebra Longwing, Gulf Fritillary, Cloudless Sulphur.

  4. Toby says

    Hi there I am living in the Tropical South Pacific and have purchased A. Currassavica seeds but have had a really poor germination rate. I have bought a potting mix because not to sure on the quality of the soil in the Garden but still there not germinating well. They are planted in seed trays, and are on table under an open garage. There is a spot light that comes on automaticslly after it goes dark is this something that can affect the germination. If you have ideas please reply ok many thanks

    • says

      Hi Toby, I soak my tropical milkweed seeds in warm water for 24 hours before planting them. You can keep the water at a good temperature by putting the seeds in a small bowl of water and placing it on a heated seedling mat. After you plant the seeds the heated seedling mat can also be used to speed up germination. You don’t need to use the spot light if they are getting light during the day. Our seedlings get about 10 hours of light. Check out this article for more info:

      http://www.monarchbutterflygarden.net/starting-seeds-inside/

  5. Wam'z says

    Hi,
    I just wanted to know how long it takes for the milkweed to mature from the cuttings when grown under Hydroponic planting method.

    • says

      Hi, I just grow them until they root and then plant them in-ground. This typically takes between 1-2 months. The system I tried to root them this season was not successful and the styrofoam inserts were causing them to rot, so I switched back to placing them in a glass of water (but this time using distilled water) and placed the glasses o my heated seedling mat.

      If you’re looking for rapid growth and full size plants, someone just sent me this info which might help:
      http://www.folksbutterflyfarm.com/aeroponics_tote.pdf

  6. Chris Hammond says

    If you live in the United States please read the following article before deciding to plant Asclepias Curassavica (Tropical Milkweed). Unfortunately, this well-intentioned effort to restore habitat may actually be contributing to the decline of the Monarch population. It is important to plant only Milkweed species that are native to your area. The article links to helpful sites that can guide you to the correct selection.

    http://blogs.kqed.org/science/2014/11/19/efforts-to-restore-monarch-butterflies-milkweed-habitats-may-be-doing-more-harm-than-good/

    • says

      Chris, this article is based largely on speculation with little science to back it up. Too many people are focused on the potential negatives of tropical milkweed when there are simple solutions for dealing with some of these problems like cutting back milkweed (to avoid overuse) for those in warm weather regions. Also, we have viable tropical milkweed in our northern garden for weeks after the monarchs are gone. If the milkweed was their cue for leaving, they’d be leaving much later. Tropical milkweed grows quickly and is a favorite egg laying milkweed for monarch butterflies. It has even been shown to have medicinal qualities that help produce healthier monarch butterflies compared to native varieties of milkweed:

      Emory University Research

      Before we start spreading speculation as truth, there needs to be more research. For now, tropical milkweed will remain one of many (both native and non-native) milkweed varieties we grow in our garden.

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