Guidance on milkweed management confuses butterfly gardeners

Confusion reigns for gardeners and Monarch butterfly enthusiasts trying to “do the right thing” managing their late season milkweed, the host plant of Monarch butterflies.

monarch laying eggs on swamp milkweed
Monarch laying eggs on Swamp milkweed, Asclepias incarnata, in downtown San Antonio November 15, 2015. Photo by Monika Mae
For the last few years, scientists like doctoral student Dara Satterfield and Dr. Sonia Altizer of the University of Georgia as well as renown Monarch scientist Dr. Lincoln Brower have recommended slashing Tropical milkweed, Aslcepias curassavica, to the ground late in the season.  Studies suggest that the year-round availability of Tropical milkweed makes Monarchs more prone to contracting Ophryocystis elektroscirrha, a debilitating protozoan parasite commonly known in Monarch butterfly circles as OE.
Until recently, Tropical milkweed, technically nonnative, has been the only host plant available for butterfly gardeners hoping to lure the migrating butterflies to their yards.  The reliable bloomer will thrive year-round in warmer and coastal climates, especially in Texas and Florida.  Scientists believe this year-round availability creates a hotbed of nasty OE spores and spreads the disease.  Its presence can also encourage Monarch butterflies to break their diapause–or temporarily suspended non reproductive state–and lay eggs, thus unable to complete their migration to Mexico.
No doubt about it: Monarch caterpillars LOVE Tropical milkweed. Photo taken 11/24/2015 by Monika Maeckle
No doubt about it: Monarch caterpillars LOVE Tropical milkweed. Photo taken 11/24/2015 by Monika Maeckle
But now, for the first time ever, native milkweeds are more available.  And judging from the government funding pouring in to milkweed cultivation and the valiant Monarch butterfly habitat conservation effort, even MORE milkweeds will be coming to market soon.  Gardeners will soon have choices beyond Tropical milkweed.

“Plant only species of milkweed that are native to your region, whenever possible.”

That’s what the Monarch Joint Venture OE Fact sheet advises pollinator gardeners like me and you.
We did that.  And like good stewards, we’ve been cutting Tropical milkweed to the ground late in the season.
But guess what?  Those native milkweeds, which have recently become available because of all the attention on Monarch habitat restoration, are thriving late in the season, too.

Egg on Texana
Egg found on Texana milkweed, Aslcepias texana, 11/19/2015. Not sure if it’s a Queen or monarch (and it hasn’t hatched yet.)  Photo by Monika Maeckle
In my yard right now, for example, I have

  • Asclepias texana, Texana milkweed
  • Asclepias incarnata, Swamp milkweed
  • Aslepias curassavica Tropical milkweed
  • Aslcepias tuberosa Butterfly weed
  • Asclepias oenotheroides, Zizotes milkweed
  • Matelea reticulata, Pearl Milkweed vine.

I sought out these various milkweeds at native plant sales, the Ladybird Johnson Wildflower Center, from our family’s Llano River ranch.  I also traded seeds with other pollinator fans, friends and butterfly breeders. At this moment, all but those I’ve cut back (tuberosa and curassavica) still flaunt green foliage, days before Thanksgiving.
Should I cut these native milkweeds to the ground as well?
The theory of OE spores building up over the season, possibly infecting migrating Monarchs would seem to hold true for other milkweeds available late in the year, not just Tropical milkweed.
“You’re right that it’s less about the plant itself and more about the seasonality of the plant,” wrote Satterfield via email.  “Any plant that grows 365 days a year in the southern U.S. and supports Monarchs year-round could lead to high levels of disease, as we understand it.”

Swamp milkweed seed pod
Drawback to cutting back native milkweeds: we then can’t harvest the seedpods. Photo by Monika Maeckle
“My personal leaning is that if the species are native, they don’t need to be cut back on a regular basis,” said Dr. Altizer via email.  “Any natives that routinely remain in lush green foliage into the fall and winter are likely going to be rare species, or it will be a rare year when this happens, whereas with the Tropical milkweed, these commonly remain in green foliage until they are hit by a hard frost or cut back.”
Dr. Lincoln Brower, always the purist, suggests even cutting late season nectar plants back–if they are growing in close proximity to Tropical milkweed.
“I have given some thought to your question of whether nectar sources might accumulate OE spores,” wrote Dr. Brower via email.  “I think the answer to this is one of probability and proximity to curassavica [Tropical milkweed]. I think that nectar sources are so diverse and abundant in the natural environment that the probability of Monarchs infecting the plants with spores is very small. …unless the nectar plant is growing adjacent to curassavica. Again, yank it out.”
Confused?  You’re not the only one.
Mary Kennedy, volunteer at the Monarch Larvae Monitoring Project
Mary Kennedy, volunteer at the Monarch Larvae Monitoring Project
Mary Kennedy, a longtime Monarch Larvae Monitoring Project volunteer and trainer said she is no longer going to advise folks to cut back their Tropical milkweed. “If milkweed is on the ground late in the season, I don’t see why it makes any difference what species it is,” said Kennedy, a former science teacher. “Grow up kids, and make your own decisions.”
One drawback to cutting milkweeds back late in the season is that we then are unable to harvest the seeds. I cut back a patch of Swamp milkweed in August as it was riddled with aphids and gangly.  The plants failed to produce any more flowers; thus, no seeds have been harvested from that patch to propagate future native milkweeds.
Satterfield insisted that the scientists’ statements are “still correct and not mutually exclusive.”
Swamp milkweed in the "wild" of the Llano River, 11/21/2015. Photo by Monika Maeckle
Swamp milkweed in the “wild” of the Llano River, 11/21/2015. Photo by Monika Maeckle
“Our research suggests that milkweeds that support Monarch breeding year-round in the U.S. could put Monarchs at higher risk of disease. The milkweeds enabling these non-migratory Monarchs are exotic species, like Tropical milkweed and Family Jewels milkweed. We are not aware of any native species supporting large numbers of Monarch caterpillars during the winter in the Gulf states. So, we do not have any scientific support right now that says we should cut back native milkweeds.”

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41 Responses

  1. Bern
    | Reply

    I planted common milkweed and learned early on that it is impossible to grow monarchs because the weeds attract ants which eat the eggs and myriad flies sitting on leaves awaiting any movement in order to pounce and lay their eggs inside of a caterpillar, which ultimately kills it. There are organic farms near me and organic farmers declared the techinid fly “beneficial” because it reliably kills …guess what….caterpillars! Tons of techinid flies released on organic farmland has resulted in virtual impossibility of successfully raising monarchs outdoors. Now if you want to devote your life to raising monarchs then you must go out into the weeds, clip off leaves containing eggs, bring them indoors, place them in a container with a mesh roof and wait for it to hatch. Then make sure you’ve got plenty of milkweed leaves for the caterpillars to munch on.

    But if you wait until they are caterpillars before bringing them indoors, chances are they’ve already been injected with eggs by the flies which spend all day on the milkweeds. Sure, the caterpillars look healthy when you bring them indoors and when they make a crysalis. But you will be repeatedly disappointed as that chrysalis turns black and eventually releases techinid flies.

    I suppose if you live somewhere that doesn’t have organic farms nearby, you might be successful. But I believe that it isn’t habitat loss or climate change that is primarily the cause of the decline in monarch butterflies; it’s techinid flies. Especially since the drastic decline started happening around the same time more and more farmers were going organic and the flies were touted as a beneficial miracle that everyone needed in their fields. The flies have now outnumbered monarchs to the point where the destruction of caterpillars makes it almost impossible to keep up a healthy number of monarch population. Go ahead and look up “techinid flies” and you’ll find two subjects — 1) how fantastic and beneficial and good for the environment techinid flies are and 2) people trying to help monarchs continually documenting how techinid flies attack the caterpilllars and the ultimate appearance of black crysalises containing more flies.

  2. Robert Burns
    | Reply

    I read part of this. I saw nothing offering competent scientific evidence that O.E. is transmitted by tropical v. “native” milkweed. I do know that “native” milkweed is just about impossible for me to grow in San Diego which is sad because it’s either that or none which I can plant at Famosa Slough. I also observed that the problem with the Tachinid fly is far worse than O.E. during the evil fly’s incubation period but that my caterpillars are now dying from microbes which no one will test. Let’s focus on getting some testing going and on eradicating O.E., Tachinid flies, and pesticide-subverted commercial milkweed. BTW, I am amazed that Monarchs are still laying eggs here; I found a 2nd instar on one of my outdoor plants today.

    • Nancee Caye
      | Reply

      Hi Robert.
      Thank you for your information. I continue to collect information, and to do research. One of my FB community members had done some of her own research and came across the information that Tachinid flies are introduced in numbers as an Integrated Pest Management for crops. So out of season, man-introduced tachinid flies are being released in large numbers, without regard to where they end up. And far too many of them are ending up killing our Monarch caterpillars.
      I contacted the CA Dept. of Agriculture and left a message about this practice and how it affects our Monarch population, and had they run this IPM by the CA dept of Fish and Wildlife. I haven’t received a reply yet .
      I’m sending an email today to the biologist who is in charge of the permit requirements for the Monarch butterfly, and letting him know what we are now fighting.
      I completely agree…my FB community has reported far more deaths by tachinid flies than any other cause. We’ve been looking for a solution but so far haven’t found anything.
      If you are interested, the link to my page is below. It’s a public page, but you can just look at the posts/photos if you like. Good group of people who are giving me reports on their numbers of Monarchs, conditions in the gardens, any other nature related information, and their location by zip code. I keep a map of locations, and a data sheet of reports. You would be welcomed if you decide to add your information and location to the map. Both the map and the data sheet are secured, and not shared with anyone. Let me know if you find anything else. thank you again for your information on this.

  3. jim sales
    | Reply

    I live in Spring Hill , Florida. I’m looking for plants or seeds for a milkweed vine. I purchased seeds from out of the country but was sent seeds for Morning Glories. Anyone know where I can purchase Honeyvine milkweed or another vine that is a host plant for Monarchs .

  4. Craig the Butterflyman
    | Reply

    This is the link to the Q & A about Tropical milkweed and its effects on monarchs put out by the lead group paid by the federal government. The common thread running through this Q & A is the misstatement when tropical milkweed is available in the winter months the “natives” aren’t. The fact is if tropical still has edible leaves in a particular area, the natives in the same area also has green leaves. Monarchs lay on both. The incident of breaking diapause or proliferation of OE is the same, native or tropical. MJV doesn’t state this fact; on the contrary. This fact has been pointed out to the people who authored this study and Q & A on numerous occasions and is ignored. This is misinformation that’s been proliferated through monarchy and the general public by not telling the whole truth, and the ignorance and misplaced trust by the general public placed in this group. The authority of those leading the MJV and the trust placed in them needs to be challenged. You are aware of this firsthand Monica observing your own milkweed on your ranch and it’s time instead of asking this question and having it be ignored action needs to be taken. Dara the writer of the study quoted in the above article said: “We are not aware of any native species supporting large numbers of Monarch caterpillars during the winter in the Gulf states. So, we do not have any scientific support right now that says we should cut back native milkweeds” Monica demonstrates in her story above there are such areas. In many years in the past with occasional rains in the summer and fall there is lots of “native” milkweed putting on leaves during migration times. There are examples on the journey north website for this year and in the archives right now. This is just another example of agenda driven “scientist” knowingly perpetuating false information. I would be interested in any input by the readers of this publication as to what actions we should take ???

  5. Craig the Butterflyman
    | Reply

    Butterfly expert and president of the North American Butterfly Assoc. gives one of the best explanations on tropical milkweed.,d.eWE The lead 501 conservation group funded with your tax dollars by U S Fish and Wildlife is heavily invested in studying the parasite OE over the last 20 ears and is forcing their “opinions” and incomplete science on the rest of monarchy which is untrue by omission of all the pertinent facts. The author of the study Dara Satterfield is a student of Sonia Altizer who is a student of Karen Oberhauser who is the director of the organization that disseminates their “opinions” down through other Monarch Joint Venture members most all of whom drink the tainted Kool Aid and teach this untrue information. Unfortunately these opinions have spread to some of the major growers in the country who have reduced production of tropical milkweed to the detriment of the monarch butterfly. Tropical hasn’t been the biggest part of their sales in the past anyway. Instead of condemning tropical you should be approaching major growers throughout the country and do as Monica and I have in convincing them to grow other varieties of milkweed that will survive drought and freezing temperatures throughout the country so they display it beside tropical in the 17,000 garden centers in the country. Colorspot did a test market of thousands of tuberosa (butterflyweed) this year because of our encouragement and I understand it went well. I hope they grow more of different varieties next year. Colorspot is the biggest grower in the country and supplies 2000 garden centers. Call or email them and thank them for their interest,d.eWE Although Tropical is a favorite of monarchs and queens it is not cold hardy above plant zone 8 and dies in the winter in most parts of the country. It’s easy to sit around and punch your keys on Facebook but this requires real involvement. This tropical milkweed misinformation needs to be rolled back by Monarch Joint Venture and its members and published on all their Facebook pages and websites

  6. Craig the Butterflyman
    | Reply

    Notice the professor says in the following article it’s the biggest migration in CA in 10 yrs. He also says there’s lots of unused milkweed. He also says he doesn’t know why “The cause or causes [of the past decline in monarch populations] remain unknown,” says Professor Shapiro. “But they are not related to the amount of milkweed; we were seeing lots of milkweed not being used because the butterflies weren’t there to use it!” Texas had lots of unused milkweed this year and the population in Mexico is said to have quadrupled
    Lots of OE and tropical flavored Kool Aid out there 😉

      | Reply

      I haven’t had many monarchs for the last 2 or 3 years. Used to have them all over. We have common on and a dark red milkweed which I used to find many caterpillars on and this year there were none. Should I buy some and let them hatch here so they will return next year?

      • nancee
        | Reply

        Dorlis, I’m curious what area you are located in.
        On my FB page, we have all come to realize that a gardener can actually have too many milkweed plants, but not nearly enough nectar plants for the butterflies (and other pollinators) to feed on.
        And everyone has a story to tell about getting too many caterpillars on their few plants, so they feel they need to buy more milkweed plants.
        I would encourage a neighbor or two to have at least some potted milkweed as well and more nectar plants. Go to your chemical-free nursery this coming Monarch season and see if any of the milkweed plants have eggs or caterpillars on them. Maybe purchase a few of those and see how that goes.
        But once you have Monarchs visiting and females laying eggs, understand that you have to set a limit on how many plants you are going to provide.
        That’s where your neighbors come in. Check with them when you have too many caterpillars, and have a neighbor or two adopt them. I know a lot of people do that. And it works better than having too many milkweed plants.
        But don’t neglect your nectar plants, and encourage your neighbors to increase their number of nectar plants as well.

        • DORLIS GROTE
          | Reply

          I liove about 40 miles north of St.Louis, Missouri in the middle of the woods on a bluff over the Cuivre River in Lincoln County. My neighbors are 6/10 mile from me in all directions. We have no nurseries, would have to go to the internet to get gmo free seed. I have the ones that grow along the roads in our area, common and a dark red one. I have been saving the seed and sending to friends in the area. For the last 2 years, we have been getting less and less Monarchs. I don’t know if this is because of farmers spraying and using gmo corn, wheat and other crops. I have a neighbor who is having trouble with his bees dying off more each year.
          I thought maybe if I bought monarchs and released them here that they might return here the following year. As for necter flowers, I have wild yellow primrose (6′ tall), wild aster, goldenrod, any thing that grows wild in our area.

          • nancee

            Dorlis, I believe that because of the weather pattern changes, you are going to have years when few/no Monarchs will find their way to you.
            Here’s a map that shows the migration path of Monarchs this year. But I don’t think it takes into account the way the weather patterns have affected the Monarch migration path.
            I still would encourage you to read as much as you can about the Spring migration paths, and get your garden ready for it starting now. Even in the winter, you can start native milkweed plants. If there is no snow on the ground, sow some more nectar sources. And be ready for the pattern to change.
            Here’s a quote from an article (I’ll list the source at the end) “Monarch waystations
            In 2012, Helm said there were only 35 waystations in Kentucky. Now, has 249 registered waystations in the state.
            There is no size requirement for waystations, Helm said. Though there is a recommendation of having at least 100 square feet.
            “The big thing to know is the type and number of plants,” she said. “Of course, we have to have milkweeds. They lay their eggs on milkweed.” It is the only plant monarch butterflies use to lay their eggs.
            “Then you have voracious little caterpillars that hatch,” she said. Helm said the common milkweed has gained popularity but to avoid planting them if there is no room for the runners they grow; swamp milkweed grows tall but has no runners, along with the butterfly milkweed that varies in shades from yellow to red.
            Helm said it is important to be sure to plant milkweeds that grow in fall, spring and summer.
            Also essential to have at a waystation is a variety of nectar plants, such as Joe-Pyes, mist flowers, showy coneflowers and marigolds.
            Groups of three
            It’s recommended to plant these in groups of three.
            “Monarchs don’t see very well,” Helm said. “So if you’ve got a big bunch of flowers, they can see that and will be more attracted by a clump of one flower versus a single plant.”
            Ensure the waystation can provide monarchs with at least six hours of sunlight a day, and good soil makes a huge difference. Helm said she is using clay from the hills of Peaks Mill, from which her waystation plants are growing.
            Helm advises against using any herbicides and says a certain level of maintenance and work is well worth the benefits.
            “Native plants will die but don’t cut the stalks until after the winter,” she said. “Some insects thrive on those for shelter in the cold, so wait until spring.”
            I like the suggestion that the milkweed plants be planted in groups of 3.
            If you should decide to buy some caterpillars this next spring, I would recommend Shady Oak Butterfly Farm. I know this woman and her family’s care in raising butterflies.
            It’s expensive. And it’s only a guess as to if butterflies will come back into your area from the caterpillars you buy.
            But maybe by doing all 3, planting a few more milkweed stands of 3, increasing nectar plants, and buy a few caterpillars, it might work.
            Are you on the Monarch Watch map for a Waystation Garden?
            If not, go to
            and go to the bottom of the page and choose Registry. That’s free. You can also certify your garden if you want to pay for that.
            Please keep in touch. I’m in Southern CA, so our problems may seem completely different. But we’ve found that this El Nino weather pattern is throwing all predictions out the window! We’re trying to map the migration and resident populations ourselves by sharing what is happening.
            If you’d like to join us, we have many people from the east in our community, and you may find some information there.
            My FB page is public, so you don’t have to have a FB page yourself.
            My page is Monarch Butterflies Southern California Style.
            Good luck, and don’t give up!!

          • DORLIS GROTE

            Have a friend in Warrenton, Missouri who is interested so sending all to her. Thanks a lot for the information.

  7. Sandra Meraz
    | Reply

    I just put this out on my blog. Thanks for the great input.

  8. Sandra Meraz
    | Reply

    I’ve just had a heated debate over tropical milkweed with a purist that insists that everyone in our larger neighborhood in Southern California pull out all of their tropical milkweed and plant natives next year. This was posted on a website for all the neighbors to see. This seems wrong on so many levels, particularly that I suspect people might pull the milkweed up and either never plant natives or have tremendous difficulty growing it. He sites MonarchWatch’s recommendations which might be good for enthusiasts but probably not for everyday people who have long standing tropical milkweed in their garden. The point I’m making is that there is a danger to the messages being sent out to the lay public about tropical milkweed which have the potential to harm the overall volume of milkweed found in states where tropical milkweed thrives. I’ve thoroughly enjoyed reading this article and subsequent posts and feel more enlightened than I had before.

    • nancee
      | Reply

      Sandra, I’m in San Diego county also. I’d be interested in hearing more of your experiences with Monarchs and milkweeds.

  9. Meg LeSchack
    | Reply

    Thanks for your diligent attention and querying regarding this issue. Is there any way for lay people to see the spores or symptoms of them, to know whether their plants are infected?

    • Sandra Meraz
      | Reply

      No, the spores are invisible to the naked eye. If you can catch the monarchs you can participate in checking them for OE under the guidance of MonarchHealth. They are always looking for research citizens.

      • nancee
        | Reply

        The only thing I would add is the way that the Monarch Health Lab has their protocol set up, you should be collecting “wild” caterpillars, and waiting for them to eclose as butterflies to test them.
        Their protocol rules out the cleaning process that can produce clean butterflies.
        They want to sample only the butterflies that result from non-treated eggs to caterpillars to chrysalides to butterfly. They are setting their experiment up to test only infected caterpillars.

        • Sandra Meraz
          | Reply

          I was asked to participate in Monach Health by Monarch Watch even though I raise the butterflies from eggs and keep them secluded and with bleached milkweed. Monarch Health still wanted me to participate by just noting that the butterflies were raised from eggs. I could’t imagine how this would help their research as surely it would be skewed,but nonetheless, they did.

          • nancee

            If anything, it does show them that by following a thoughtful and careful protocol, one can raise O.e. free butterflies.

    • nancee
      | Reply

      Monika, are you ok with me answering these?
      Meg asks an interesting question:Thanks for your diligent attention and querying regarding this issue. Is there any way for lay people to see the spores or symptoms of them, to know whether their plants are infected?
      For any gardener with curiosity and (as you say) diligence can learn to test the butterfly for the presence of O.e. spores. I have a tutorial on my facebook page showing an easier way to test the butterfly with clear tape. Monarch Health Lab uses clear tape as well, and stresses that it must be clear tape vs opaque type tape. At this time, only the butterflies can be tested, and the tape sample put under a microscope with a magnification of at least 100. I took test samples for Monarch Health Lab for a year in 2014-early 2015. I then sent the test samples to their lab to be looked at under the microscope. It took some time for them to let me know what the results were…but they get a lot of samples, and it isn’t a fast process. I had a 100% infected rate of the test tapes sent to Monarch Health Lab…all of my butterflies were infected.
      This Monarch season I bought my own microscope and started “reading” my own samples.
      Remember tho, the only life stage you can currently test is the butterfly. If you put “O.e. spores on Monarch butterflies” into your search browser, you’ll find quite a bit of information showing the complicated life cycle of the O.e. spore. It can only reproduce once it is ingested by the Monarch caterpillar. Once in the caterpillar’s gut, its reproduction begins. Basically, in this process, the O.e. spores eventually make their way through the developing butterfly’s body (in the chrysalis) to be on the surface of the butterfly’s body, and capable of dropping off the body. O.e. spores are a lot like glitter; glitter can scatter easily, and so can the O.e. spores.
      At any time the infected butterfly moves, the spores can drop off. I’ve been told the number of spores on a butterfly can number in the millions. I haven’t verified that. So an infected butterfly can fly over any plant and spores will scatter on the plant, the soil, and any other butterfly that might be there. Those spores cannot hurt the uninfected butterfly, but those spores can hitch a ride and be scattered on the host food of the caterpillar~~milkweed. And the cycle starts over. I asked about testing the milkweed plants, but was told they had never done that. So I tried this summer, but so far have not found the spores. But my Monarch season was interrupted by a stroke, so I’ll try again next year.
      So Meg, the plant isn’t infected. It just may have O.e. spores scattered on its leaves and/or soil by infected butterflies.
      Several people on my FB page tried bleaching both the eggs (which can have the tiny spores on them and be ingested first thing by the hatchling) or the leaves they use to feed them. Again, you can find instructions on the web. I used plain water. I thoroughly (but carefully) rinsed the leaf with the egg in water vigorously enough to break water tension in the valley of the egg’s ridges. I also rinsed the leaves I fed these caterpillars. And I had a 100% rate of clean butterflies~~no infections. I raised another 20 out in the yard on plants that i kept rinsed, and the rate came down to about 70% clean butterflies. I let the eggs and caterpillars alone in the yard, and had a rate of only 60% clean butterflies, meaning no infection.
      So evidently water can rinse these spores off of the food source that is usually where the caterpillars ingest them and become infected.
      Like I said, the experiment will continue this next Monarch season, which usually begins in early April.

    | Reply


    • nancee
      | Reply

      From my studies and correspondence with others, the best that is understood, only bleach seems to kill these spores if you are wise to go a more “natural” way and avoid any other chemicals.
      Put “How to kill O.e. spores” into your search browser and look at the post that mention using a bleach solution to clean eggs and milkweed leaves.
      As far as I know, that’s the only method of killing the spores outright.
      I’ve search a lot to find some natural way to fight the spores, but it appears that not enough is known about the spores to suggest a predator of the spores. And we need to be careful introducing any other life form just to kill the spores. The balance of nature could easily be tipped and harmed.
      And so far, no one can even tell me how long O.e. spores can remain dormant and still be viable. That in itself seems to beg for more research.

        | Reply

        What if I use water spray to wash the spores off my plants? Can i see them or would I need a magnifying glass to see them?

        • nancee
          | Reply

          The water spray has to be fairly strong, so a water bottle won’t spray off many. And no, you can not see them by naked eye or through a magnifying glass.
          You need a strong stream of water, and you need to agitate that leaf with the egg vigorously (back and forth and around).
          I put a dark color bowl under the leaf with the egg that I rinse. So far, I only had one egg come off the leaf and land in the bowl. I slid the leaf under the egg, but the egg is no longer “anchored” to the leaf quite the same. But if you are careful, you can get that egg to sit on the leaf and have it hatch.
          Just to be clear, you only do the rinsing of the egg and the leaf it is on once, when you bring it in.
          But you also rinse and swish the leaves that are being feed to the caterpillars as well each time you bring a new batch in.
          One thing that hasn’t been brought up is how we stage the chrysalides to eclose. I think that it is important to remember that NOTHING should be under the eclosing butterfly. Not even another chrysalis and definitely no caterpillars or food leaves. If they have the O.e. spore infection, those spores are going to spread as soon as it clears that chrysalis. So keep everything out from under the chrysalides. Even lab notes. And constantly clean the surface that is underneath them.

    | Reply


    • nancee
      | Reply

      Dorlis, that decision is really up to you. Native purists will say no. But there are many of us who feel the better the diversity of milkweed plants, the better the butterflies will do. I do like your idea of staying within a similar zone as to where you live.

  12. nancee
    | Reply

    This edict to cut back milkweed and/or nectar plants makes no sense. Yes, spores can accumulate on anything, including the soil. And what are we going to do about the soil. That is supposedly where the O.e. spores are naturally found.
    Instead, good management can be simply cleaning up a plant that has been eaten to the stalk by either rinsing thoroughly, or using a bleach mix of at least 10% bleach to water, or hydrogen peroxide with water at a 50/50 rate. Spray well, and rinse well.
    But right there is a possible answer~~RINSING.
    If a gardener is rinsing their plants, whether milkweed or nectar, those spores that “fall like glitter” can be rinsed off the plants.
    But now it’s on the ground, so what to do?
    Rinse. And rinse again. Scoop out the top layer of soil and replace with fresh layer, and maybe some mulch.
    There are easy ways to handle this.
    My concern is that researchers/scientists want the Monarchs to follow the same pattern each and every year!
    The Monarchs are creatures of nature and will adapt. And that adaptation will possibly mean a change from the same old pattern.
    Why can’t they understand this?
    I like Mary’s comment: Grow up and make your own decisions based on your own research and your own experiences. (Sorry Mary, I kind of paraphrased your quote)

  13. Cheryl Wells
    | Reply

    One other thing… I often will cut back SOME tropical milkweed plants and leave others so there will be some milkweed growing. I let it grow wherever it comes up, so I usually have a lot of it around–some cut back and some full size.
    However, I suspect the native varieties will not need this kind of cutting. The a. tuberosa plants I purchased have been slow to start and thrive for me, so I’m still learning how to grow them. I am trying native seeds next spring. I don’t intend to prune them–I just want them to grow!

    • janet rowland
      | Reply

      can you tell me if milkweed pods are ruined if a killing frost hits, some of my pods weren’t dry then we got a frost? also could I have cut some back and hung them upside down to dry on the stem? please help. my email is ;,, thank you

  14. Paul Cherubini
    | Reply

    For many years the “don’t plant tropical milkweed along the California coast” and “don’t purchase and release commercially reared monarchs” advocates have expressed deep concern that these human activities have the potential to increase the OE infection rate in the
    migratory monarch population. Example:
    We now we have the data on the OE infection rate of the migratory overwintering monarchs along the central California coast in 2014 vs similar data than was recorded by three groups of researchers in the late 1990’s and early 2000’s (Dr. David Marriott of the
    Monarch Program, Dr. Sonia Altizer of Project Monarch Health and Dr. Dennis Frey of Cal Poly San Luis Obispo).
    The 2014 data show that surprizingly, the OE infection rate was remarkably low – a mere 5.53% – far lower than was recorded by the three camps of researchers in the late 1990’s and early 2000’s.
    Thus we see that the 2014 data do not support the hypothesis that planting tropical milkweed and releasing commercially reared monarchs has the potential to increase the OE infection rate in the wild western migratory monarch populations.  

    • nancee
      | Reply

      I’d be interested in knowing what documents you have that show O.e. test results done by the 3 researchers you mention.
      I haven’t yet read the document that you provided. But my caution would be to have several years of studies before making any assumptions. Because right now, it is all still assumption based on part of one year’s sampling. Even the paper you cite has the following statement: ” These samples will help inform parasite infection rates in the Western Monarch
      population. ” Help inform.
      There is another huge problem with this study in regards to the southern CA Monarch populations~~no Monarchs were tested in southern CA. And again, you would be making an assumption if you were to extend the same results of the test to the southern CA population.
      I participated with the Monarch Health Lab this past winter, during the same time period that the samples were being taken on the northern CA population. I know of several people who also participated. It was clear that the rate of O.e. spore infestation was high.
      Paul, you assume too much about too many things. It takes years of tests and re-testing from many different sources to come to any definitive answer to this problem with O.e. infestations.
      Again, l would love to see the documentation you refer to for the testing done from 1997 – 2000.

      • Paul Cherubini
        | Reply

        Nancee, see Table 4 on page 133 that shows around 25-40% of the monarchs at several overwintering sites along the central California coast were heavily infected with the OE parasite during the 1989-90 overwintering season vs only 5.53% in 2014. Back in 1989 there weren’t any companies in the USA selling farmed monarchs for release at weddings and retail nurseries did not stock evergreen tropical milkweeds.

        • nancee
          | Reply

          Paul, do you only have this one document?

          • Paul Cherubini

            There are many more that show OE spore counts in the 1990’s were far higher than they are nowadays. Like this 1996-97 fall-winter OE spore count study by David Marriott

          • nancee

            Paul, the articles and papers you are citing are at least 20 years old. There is no way to verify his results or his testing protocol.

          • Paul Cherubini

            Nancy, David Marriott’s 1996 spore count results (23-53% of the clustering butterflies along the central California coast were heavily infected) mirrors the results two other research camps (the Altizer Lab and Cal Poly San Luis Obispo) obtained during the 1990’s and early 2000’s. But in 2009 the Louis Yang lab at UC Davis found low counts as did the Altizer lab in 2014. So we have multiple sets of data that document a dramatic decline in spore counts in the overwintering, clustering butterflies along the central coast in the late 2000’s and early 2010’s as compared to the 1990’s.

  15. Cheryl Wellsc
    | Reply

    I have always suspected that native milkweeds will have the same problems as tropical milkweed–once we start growing lots of it. Our problem in Houston is that many milkweed varieties will probably not die back very much in late fall. I actually cut my tropical milkweed back twice a year–in the middle of the summer (after the leaves start looking diseased) and in late fall/early winter. The plants seem to be healthier and have better foliage. You do have to water them some, but they seem to recover. Whether this helps the butterflies, I don’t know.
    I have had so many red paper wasps in the past that they killed most of the caterpillars I had. This year the wasps built in the soffit vents of the house, and things came to a head when I tried to clean out the gutters and found twenty little beady eyes watching me! At this point, I killed a lot of them, and now I am hoping that my milkweed will host more caterpillars. I actually like wasps, and they are beneficial, but enough was enough. Perhaps things will come back into balance more in my yard and the monarchs will have more of a chance. I have just started trying to grow the native varieties, so I don’t know what will happen with that.
    It just seems that with the tropical variety, the plants themselves do better with more pruning than once a year.

    • nancee
      | Reply

      I agree that pruning might help with the O.e. infestations. But we have to remember that the spores are not picking Tropical milkweed plants. Any milkweed plant upon which an infested female oviposites will have spores dropped on it. So will any nectar plants the female or male might visit. O.e. spores are out there, but there are ways to keep the number of spores on your plants down. Any plant. Rinse the spores off your plants on a regular basis. Replace the top inch of your soil beneath the plants. If a milkweed plant is eaten down, clean it up and set it aside to recover, while continuing to rinse and replace the top inch of soil. I don’t have to trim any of mine down. The caterpillars do that for me. So I swap out eaten down plants with “clean” plants as needed.

  16. William Grant, Ph.D.
    | Reply

    I agree with Mary Kennedy. The science behind the Tropical Milkweed scare is very soft at best. People who raise Monarchs on tropical milkweed on social media have not reported higher rates of Oe than those who use “native.”
    Again the numbers of milkweed available for Monarchs to host upon is the issue. If we want to increase the numbers of Monarch butterflies we need to increase the numbers of milkweed, of all kinds. Until Oe has been proven to be a significant threat ignore the cut it off talk.

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