Milkweed for Monarchs

w-sig- Monarchs(mating)

Mating Monarchs on Common Milkweed in Sutton’s Garden

There are over 2,000 species of milkweed in the world. 108-110 milkweed species are native to North America. ONLY 27 of these are used by Monarchs as host plants.

Those of us wishing to create Monarch Waystations  full of nectar and caterpillar plants need to do our homework to learn which native milkweeds Monarchs will lay their eggs on. Planting species native to your region is key.

w-sig-waystation

Monarch Waystation in Sutton’s Garden

 

Native Milkweeds Region-by-Region

Monarch Joint Venture has done the homework for us; their milkweed information sheet presents the best native milkweeds region-by-region (Northeast, Southeast, South Central, Western, California, and Arizona). They also provide a directory of native plant vendors that sell milkweed plants and/or seeds.

If you want more exact information about where each native milkweed grows, visit the Biota of North America Program’s North American Plant Atlas Asclepias page for distribution maps for each milkweed species across the continent.  The distribution maps in the USDA’s plants database for Asclepias (Milkweed) are also very helpful.

Teammate Carole Brown in her post “can milkweed be bad for Monarchs” took a close look at some of the reasons non-native milkweeds should be avoided.   This followed Kathy Villim’s post at Beautiful Wildlife Garden about her visit to a Monarch Butterfly wintering site in California where docents had been advised by experts to remove milkweed that had been planted at this overwintering site because it was disrupting the migratory cycle.

Living at Cape May, a Monarch migration hotspot, I wanted to throw in my two cents. Not only do we see some terrific concentrations in the fall, but Cape May wildlife gardens are nurseries for generation after generation of Monarch spring through fall.  As an environmental educator Monarch Lab has answered so many of my questions about Monarchs and milkweeds.

Cape May Has a Mix of Populations in the Fall

  • migrants from the north that are passing through (in sexual diapause, no longer interested in breeding, but instead entirely focused on migrating)
  • locals that are enjoying Cape May’s microhabitat (buffered by the warm waters of the Atlantic Ocean to the east and the Delaware Bay to the west) and continuing to breed, lay eggs, create the next generation, and die.  We’ve found eggs from these locals as late as early November.  It’s a lottery, of course, since it will take at least one month for the life cycle (egg to adult).  If a freeze occurs these late eggs, caterpillars, chrysalises, and adults might not survive.  But if no freeze occurs, the population has grown by one more generation.
Monarch on Tropical Milkweed

Monarch on Tropical Milkweed

Tropical Milkweed, an Annual

I’ve planted all the milkweeds native to South Jersey in my garden. Some have flourished (Common Milkweed and Swamp Milkweed). A few have limped along (Butterfly Weed – my soil is just too good, not barren enough). Some have come and gone (Poke Milkweed, Whorled Milkweed), unhappy in my garden.

Tropical Milkweed eaten to the bone by Monarch caterpillars

Tropical Milkweed eaten to the bone by Monarch caterpillars

As a wildlife gardener I compliment my native plant garden with annuals. They’re easy to grow, forgiving when nature scorches or saturates the soil, they’re non-stop bloomers, and they readily regenerate when nibbled. Tropical Milkweed is just such an annual that I save room for in my garden each year.

Tropical Milkweed is an amazing Monarch caterpillar plant.  I’ve seen it eaten to the bone (with only the stems remaining) and watched in awe as it regenerates new leaves, buds, and flowers like the Energizer Bunny.  I’ve watched individual plants regenerate multiple times over the course of the summer and fall.

w-sig-hand of monarchsSome years there are so many eggs and caterpillars on my Tropical Milkweed that it barely has a chance to regenerate. I’ve stepped in and moved hundreds of caterpillars to my stands of robust Common Milkweed plants to give the Tropical Milkweed plants a chance.

Moving Monarch caterpillars from stripped Tropical Milkweed to Common Milkweed

Moving Monarch caterpillars from stripped Tropical Milkweed to Common Milkweed

Tropical Milkweed does not survive the winter in my garden. I would probably reconsider and steer clear of it if that was the case. With global warming I may yet need to take that stand. But for now, Tropical Milkweed has a place in my garden and offers nectar to so many different butterflies for many months and serves as an excellent caterpillar plant for hundreds upon hundreds of Monarchs.

Monarch Watch shares that gardeners living where Tropical Milkweed survives the winter have taken to cutting it back to the ground from time to time so that new growth regenerates and hopefully lessens the possibility of the protozoan, Ophryocystis elektroscirrha (O.e.), surviving on the plant.

Never Enough Milkweed

Too many roadside stands of milkweed are mowed down.  In my mind, the responsible gardener can’t offer enough milkweed in their habitat.  The more patches of milkweed scattered hither and yon, the better the chances of Monarch eggs, caterpillars, chrysalises, and adults surviving predators.

Pat Sutton, of Cape May NJ, is an author, educator, and naturalist who has taught gardening for wildlife workshops and led tours of private wildlife gardens for over 30 years. She shares her passion around the country at festivals and conferences and is available to speak to your group or organization.

© 2013 – 2014, Pat Sutton. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. We have received many requests to reprint our work. Our policy is that you are free to use a short excerpt which must give proper credit to the author, and must include a link back to the original post on our site. Please use the contact form above if you have any questions.

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Comments

  1. says

    Pat, I’ve just put tropical milkweed on my list of must-plant annuals for 2013. How do you care for it once it’s been ‘eaten to the bone’? Do you leave the stems standing or do you cut them back? I’m really hoping I’ll have the same issue in my garden in a few years and I’d love to know your preferred maintenance routine for this plant.
    Debbie recently posted..3 Native Spring Ephemerals for Your Garden

    • says

      Debbie, you’ll certainly enjoy it in your garden. A solid bed of it is stunning, especially with the added sparkle of pollinators and nibbling Monarch caterpillars. I feel like a big kid every time I walk by my patches of it. Peeking under leaves looking for eggs and caterpillars.

      Regarding the care of Tropical Milkweed, I just sit back and watch the show. No care needed. It can look brutalized – bare stems galore. Even then Monarchs keep laying eggs on it (hence my vigilance, moving them to robust Common Milkweed plants so the regenerating Tropical Milkweed plants have a chance). Be patient. Keep an eye on it. It slowly begins to send out new growth. Before you know it, it is blooming again. Don’t know how to better describe this annual, than as the Energizer Bunny of the plant world.
      Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

  2. says

    Great article, Pat! And having been in your garden and seen the Tropical Milkweed eaten down to nubs by hundreds of Monarch caterpillars, I can attest that they really seem to like this plant. From what I understand, if you live in South Carolina or south through Florida and across through Texas and Southern California, those are the places where the Tropical Milkweed is causing problems (for now). Anyone north of those areas will find the Tropical Milkweed to function as an annual, and should be ok until the climate warms even more.
    Carole Sevilla Brown recently posted..My Interview on Real Dirt With Ken Druse

  3. says

    Pat:
    I use tropical milkweed too – it has a much longer season than the others and seems to be more visible to the Monarchs. Frost usually gets it in November in Virginia.

    Sadly one big problem for monarchs is the use of round-up ready seed in the vast corn and bean agricultural areas of the country – kills all the common milkweed in hundreds of thousands of acres. Add to that the unnecessary tidiness of state highway departments mowing all the medians…so I plant and grow the natives and the tropical asclepias with abandon! A small contribution to a beautiful species.

    • says

      Hi Donna, YES as an annual it certainly has an endless blooming period compared to the native perennial milkweeds with their lovely but finite blooming period. November frosts normally do in my patch in South Jersey too.

      YES, so glad you brought up some of the other sad reasons to garden with a vengeance or with abandon (as you so beautifully put it) and offer as much milkweed as possible. Too, looking around at typical gardens we wildlife gardeners often feel compelled to create some lovely “over the top” gardens spilling over with nectar and caterpillar plants.
      Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

  4. Nancy says

    After several years I finally got a good stand of common milkweed to grow. As soon as they grew tall they disappeared. I watched and saw a groundhog felling the milkweed like a beaver does a tree. By the time the butterflies were ready to lay there eggs, there were no milkweeds. Do you have any suggestions.
    You should know we have very athletic groundhogs, they were able to scale a 12 foot fence.

    • says

      Nancy, jeeeeeeeeezzzzzzzzz! I feel your pain. Groundhogs are here in South Jersey but have not (yet) reached the southern 20 miles of the Cape May Peninsula (where we live). If the groundhogs felled your milkweed, there’s a good chance the roots are still intact and next year will send up an even denser stand of Milkweed. Now the trick will be to keep the groundhogs out this next growing season. I’ve heard that laying wire fence down on the ground around a garden can keep deer out of a garden (since they don’t like to walk on the fencing). Does anyone living in groundhog areas know if that works for groundhogs too? Any other suggestions for Nancy?
      Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

  5. says

    Terrific post Pat! I agree that the more milkweed the better . . . especially the native to one’s area kind. What a shot of your hand full of caterpillars. I love those little striped critters. Wonderful photos throughout this piece. It is worrisome here at times when the deer and rabbits eat the young common milkweed plants (eggs and caterpillars along with the greens.) I usually sight the first Monarchs in the garden and watch for the females laying eggs so I can collect the small plants in our paths. The time I spend raising Monarchs each year is precious to me and hopefully some make it to your garden and all the way to Mexico.
    Carol Duke recently posted..Recalling Landscape Tapestries of Spring Twenty-Twelve

    • says

      Carole, it was amazing to search my stripped bare Tropical Milkweed stems, find a dozen or so Monarch caterpillars eating them down to the ground, gently pry them off, and move them to my robust Common Milkweed plants. And a day later I’d be flabbergasted to find another dozen (which I’d gently move), and another dozen the day after . . . Thank goodness for my happy stands of Swamp Milkweed and Common Milkweed. Some summers Monarch caterpillars have stripped my Swamp Milkweed stands and they don’t successfully regenerate like the annual Tropical Milkweed.

      I’ll bet some of your Monarchs certainly do make it to my garden and all the way to Mexico. Keep enjoying the magic of Monarchs and milkweeds.
      Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

      • says

        That is incredible Pat. I have never seen the likes of your caterpillar numbers in my gardens. I think I have far too many predators here. I only have the Common Milkweed growing pretty much wherever it wants. You must have amazing butterfly counts there too. You have helped create a real paradise for wildlife there. Truly an inspiration.
        Carol Duke recently posted..Gazing Into A Wintry Landscape of Wonder

        • says

          Carol, it’s not like this every year (dozens upon dozens of Monarch caterpillars on my Milkweeds), but when it’s good, it’s very very good. The garden is indeed an oasis and soothes the soul. Can get lost in it with all one finds, as you know with your own oasis. For the last 4 or so years we’ve kept daily records of butterfly species and numbers (when we’re able, and not off working or playing elsewhere — my husband is the numbers guy). It can be pretty astounding. Last year highest diversity was on July 25 with 27 butterfly species in the garden. 2011 we had 22 species in the garden on a number of different days. 2010 we had 31 species on July 27. Fun stuff looking back on it.
          Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

    • says

      Kevin, COOL! Last year we stopped mowing a chunk of our lawn (outside the garden) and let it grow up as a meadow. I speeded up the process by planting volunteer Little Bluestem and Common Milkweed and Purple Coneflower in our “baby meadow” and they all took. May you have much luck with your milkweed and may it bring you lots of fun visitors (pollinators, egg-laying Monarchs, and more!).
      Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

  6. says

    As a Floridian, I will reiterate and problems of planting scarlet milkweed (Asclepias curassavica) in our area. Please, if you live in our ecosystems, read http://edis.ifas.ufl.edu/uw311, specifically the section on “The Threat of Nonnative Milkweeds”.

    One of the problems I see with the internet is that often people don’t hear the part about “in your particular area” and just go full blast, somewhere along the lines of “I heard that tropical milkweed is an absolute MUST for gardening. The monarchs can’t get enough”.

    They don’t bother to listen to the imperative “right plant, right place” followup.

    If there is a native available in your area, please choose it over an exotic import. Plant for nature.
    Loret recently posted..One for the Bugguide record books!

  7. DeAnna says

    I loved this informative article! My butterfly garden is 2 years old. I’ve spent every winter weekend researching & planning improvements. I went to the map, & was relieved I planted the native Milkweed for this area, I’m in Chicago. I have Tuberosa & Swamp. Here in Chicago, the winters will kill the Tropical, which I’ll start indoors in a few weeks. I will watch it, & our changing climate. We had brutal winters here my whole life, but the last 2 have been unusually warm. I have 10 Liatris Ligulistylis that should bloom in late summer, just in time for the migration south. Unfortunately, it had bloomed 2 months early, due to the unseasonably warm weather. It was dead & brown when it should have been in full bloom. The plants are confused. We need to heed their warning.

      • DeAnna says

        Thank you Pat! I’ve done a lot of research, & Wren Song has been an extremely valuable educationl source! I would love to make the workshop, I’m in Chicago, but if I can I will atend.
        I’m going to be putting in a salt/ puddleing area, for my butterfly garden, but I’m not sure how to go about this. I read somewhere to use water softener salt tablets, but I’m not sure if that is safe or the correct way to do this. Do you have any articles or links that would teach me how to make this?

        • says

          Hi DeAnna, We wrote about “puddling” in our book, How to Spot Butterflies (1999). Yes, often what butterflies are getting from puddles is nutrients and salt. I’ve never heard of putting softener salt tablets into a water source for butterflies.

          You could use a shallow bird bath that you can lay on the ground, fill it with sand. Then (I kid you not) pour urine from a male member of your family into it, enough to moisten the sand. Add more urine (from a male member of your family) as needed to keep the sand moist. Female urine does not attract butterflies, but male urine does. The early lepidopterists (and probably some still) when exploring a site would often pee at a spot they knew they’d be walking by again. Upon their return they’d often find puddling butterflies at that spot.
          Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

          • DeAnna says

            Well Pat, I’ll be having a very interesting rather hilarious conversation with my son about this, but I really don’t think my son will pee in into that, lol. So, I don’t have to add any kind of salt to this? How do they get the salt nutrients out of the sand? I’ve read they need salt, but there is lots of false info out there, (like the water softening tabs) so that’s why I’m seeking your expert advice. Do I need to add rocks or water? . Where can I buy your book?

            • says

              Hi DeAnna, The urine has salts and other nutrients, etc. in it that attract butterflies (so no need for additional salt if you have a source of male urine). Often when you find butterflies puddling on a sand road in the wild it is where an animal urinated. As long as the sand is moist, there is no need to add water. Add rocks if you want, but not necessary (though may add visual interest to you). You can find links to the books my husband & I have written on our website (in the right hand column). Happy Gardening, Pat
              Pat Sutton recently posted..Gardening for Wildlife Workshops, March 2013

Trackbacks

  1. [...] Milkweed for Monarchs “There are over 2,000 species of milkweed in the world. 108-110 milkweed species are native to North America. ONLY 27 of these are used by Monarchs as host plants. Those of us wishing to create Monarch Waystations  full of nectar and caterpillar plants need to do our homework to learn which native milkweeds Monarchs will lay their eggs on. Planting species native to your region is key.” by Pat Sutton [...]

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