How To Control Aphids On Milkweed Plants

9 Good Ideas for Keeping Milkweed Aphid-free…and 1 Bad One!

Aphid control is essential if you want to grow healthy milkweed plants for monarch butterflies. Here are 7 ways to control aphids organically, and save more milkweed for monarchs.

One problem that plagues almost all gardeners across North America is the relentless attack of oleander aphids. They suck the life from milkweed like little orange vampires.

The degree to which their infestations effect plant health is debatable, but the ugliness they unleash upon your butterfly garden is not!

Aphids on Common Milkweed
A Common Pest

In 2011, they showed up in droves on our tropical milkweed. I cringed every time I walked by those plants and wondered if I should replace the tropical milkweed to cut down their numbers?

A couple gardeners assured me the milkweed would be OK. Miraculously, I even found two 5th instar caterpillars crawling over the orange-covered leaves!

However, the seeds I collected that season gave me a better indicator of milkweed health…only 20% of those seeds sprouted the next season! Every other year without heavy aphid infestations, seed viability has been about 90%.

Keep in mind expectant monarch mothers will also avoid laying eggs on aphid-infested milkweed leaves…and if they did, would you ever be able to find them?

Little did I realize, I could have stopped our infestation from getting so out of control. Over the years I’ve learned more about treating aphids and preventing infestations, so I’m here to help you avoid our aphid-blanketed milkweed debacle of 2011.

Of all the questions I receive about butterfly gardening, “how can I control aphids on my milkweed?” is probably the most frequent. A good idea for all gardeners is to check your plants regularly. Below, you might see two harmless aphids sitting under tropical milkweed flowers…

Two aphids looking innocent below tropical milkweed flowers
Aphids In Bloom

…but I see the potential beginnings of an aphid army!

Here’s are 8 tips to keep that aphid army from ever forming, so you can save your precious milkweed plants for monarchs:

Before you try any of these methods, rescue any monarch eggs or caterpillars from harms way and relocate to other milkweed, or try raising monarch butterflies inside:

1. RUB THEM OUT: some people simply get rid of aphids by rubbing them off with their fingers and thumbs . This can be effective when the numbers are low if you’re not afraid to get your hands (or gloves) dirty.

2. HOSE THEM DOWN: a steady stream of water on the aphids can also displace them. You’ll need to hold the milkweed plant with your other hand to avoid stem breakage. Using a spray bottle on stream is also effective.

3. ALCOHOL OVERDOSE: This was reported in the LA Times as the secret to killing milkweed aphids and not monarch eggs

Please note that if isopropyl alcohol is applied directly to monarch eggs or caterpillars it will kill them.

UPDATE: Community Member Joe G. says he uses a small spray bottle filled with isopropyl alcohol to spray the aphids on his plants. After about 5 seconds, he hoses the plant down with water and those pesky milkweed invaders are dead. This sounds like a great idea, but I would only recommend this for heavy infestations…don’t destroy your local ecosystem with an aphid-free garden!

4. WASH THEIR MOUTHS OUT: a little soap never hurt anybody, but it can kill those pesky aphids. There are many homemade “recipes” floating over the internet. Obtaining information from credible .edu sites can help to avoid creating dangerous concoctions that harm plants or surrounding wildlife: Aphid Control: Soaps and Detergents

5. DIVERSIFY and SCRAMBLE: This preventative measure can become very effective as your milkweed patches start to mature. Try planting several species of milkweed, and put them in several areas of your yard and garden. The aphids will likely have a favorite area and you can sacrifice one small patch to the angry aphid gods.

More milkweed varieties could attract more aphid predators too. Could it also attract more monarch predators? Yes, but that’s a good excuse to bring a few eggs/caterpillars inside to watch the amazing process of monarch metamorphosis.

Still have aphids? You have a couple options left to regain aphid control. Unfortunately, this next option option is unpredictable and could have unintended  consequences…

Biological Pest Control can be an effective weapon in the war against aphids. However, there is an important caveat to consider...

6. WHO’S BUGGING WHO NOW?!: Introducing beneficial insects to eat the aphids sounds like a great natural solution, but beneficial bugs like ladybugs and mantids also feed on monarch eggs and larvae. There are already enough monarch predators in your garden…what will happen if you unleash thousands more?

7. REPEL WITH PLANTS: Some plants, including onions and marigolds, have been shown to repel aphids and naturally reduce their numbers. Planting these repellents close to milkweed can attract more butterflies while keeping aphid numbers down to reasonable levels.

'Summer beauty' allium flowers not only attract butterflies and bees, they also repel aphids and can save your milkweed plants from a heavy infestation that will keep monarchs away.
Butterfly Attractor | Aphid Repellent

California Butterfly Lady, Monika Moore, takes thin strips of banana peels and places them on milkweed stems near buds/blooms where aphids like to congregate…not appealing to aphids!

How to Stop Aphids from Taking Over Milkweed- Repel them with Banana Peels
Photo Courtesy of California Butterfly Lady

8. CUT IT OUT: If it’s come to the point where aphids have completely engulfed your milkweed, cut back all areas of moderate to heavy infestation and throw out. Make sure to discard the cuttings far away from the garden to avoid a touching aphid-family reunion. I suggest using a yard waste can if you have one.

Then, try options #2 , #3, or #4 on less crowded areas so they can’t start another infestation.

Aphids lay eggs when it starts to cool, so cutting down the mating population in late summer/early fall can help you avoid an aphid Gardageddon next season!

Cut Back Aphid Infestations on milkweed each Fall if you want less aphids next spring.
9. SUCK THEM UP: This aphid-control strategy was recently shared with me and it eliminates the aphids without using any harsh chemicals or hurting the milkweed.

Stop Aphids from Taking Over your Milkweed Idea 9- Aphids in a Vacuum
Photo, Video, and Idea Courtesy of Patrick J Gleeson, San Diego Ca.

Patrick attached a micro attachment for his full-sized vacuum cleaner, but you could also try the crevice tool on a handheld vacuum cleaner too. (We have one on our dirt devil.)

How effective is this strategy? Video doesn’t lie:


10. A BAD IDEA: You could also apply a professional grade pesticide like malathion, but it’s likely that monarchs, other wildlife, and the environment could suffer injury (or worse) from using harsh chemicals. There’s a reason butterfly gardeners use organic pest control…it won’t kill the butterflies!

Whatever solution you choose to control aphids, remember that early intervention is your best chance for for defeating these sap sucking pests.

Have any of these techniques worked/not worked for your milkweed? Have you controlled aphids with other methods? Please comment below and help other gardeners avoid the wrath of milkweed aphids. Thank you!
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Comments

  1. John U. says

    First off, it’s GOOD to see this site on Facebook. The monarch butterfly needs our help anyway we can do it considering the low population that they had in their wintering sites in Mexico.

    I believe the MAIN thing that can help with increasing the monarch population is EDUCATION! You’d be surprised (or maybe not) at how many people do NOT KNOW that milkweed is the ONLY plant that the monarch needs to breed and survive! And, as mentioned above, when some people hear the word “weed,” that’s enough for them and they fee they have to destroy it. It wouldn’t hurt for those of us that love the monarch butterfly and want to see their population increase to “spread the word” in our local communities.

    I’m thinking of talking with local borough officials in possibly setting areas apart to grow milkweed and to encourage it’s growth in certain areas where it would not be considered a nuisance. I’d LOVE to hear your thoughts and comments on this. Thanks!

    • says

      Hello John,

      thanks for your insightful post. I also believe that education is a key factor in getting the monarch population moving in a positive direction. Getting local officials to start planting milkweed in non-nuisance areas is a great idea.

      Another idea is to educate gardeners about the different milkweed species and cultivars available. Not everyone wants a garden filled with native milkweed that can potentially be invasive with underground rhizomes and seeding. I respect that. Instead of telling people what they NEED to plant based on scientific theory, I try to explain the options along with the potential issues and benefits. I currently have 8 species of milkweed growing in our garden (both native and exotic) and they all get used by the monarchs at some point in the season. A few of these species would not be recognized by most as a “milkweed” plant.

      I think anything we can do to get more milkweed into our communities is worthy of consideration since not everyone has the same motivations for growing it.

  2. Ethel Nylund says

    I would like to know what causes the milkweed to get all sticky on the leaves. I have not gotten the first Monarch this year and I am really disappointed. Any others have this problem?

  3. Don Young says

    I’ve had more yellow aphids than ever on my tropical milkweed and they’re way out of control. I should have started hosing them off early but didn’t get around to it as I have dozens of plants in my backyard. However, I’ve also had more full-grown caterpillars on my plants than ever before. This is now late January and we’ve had temperatures in the 70s and 80s here in southern California for the past 2 months. A few days ago I found 6 or 7 Monarch caterpillars and several were almost full-grown.

    I’ve begun cutting down the plants as much as I can without disturbing the caterpillars. As soon as I see aphids on new growth I’ll be sure to hose them off.

    • says

      Hi Don, sorry to hear about your infestation…the last time we had one (in 2011) I also remember finding large caterpillars on the same milkweed. The problem with the aphids is that they hurt the milkweed. I took seeds from those plants in 2011 and the germination rate was horrible…not to mention, they make the plants look sickly and disgusting.

      In 2012/2013 I noticed more lacewings and ladybugs in our garden. They’ve taken care of the aphids since 2011…hopefully some of their predators discover your garden! Congrats on all your monarchs and good luck keeping those aphids at bay…

  4. Sarah Dalton says

    #1 is my favorite — I prefer to think of them as orange bubble wrap!!! They pop so nicely! Just don’t lick your fingers or rub your eyes…

  5. says

    Hi guys, I too am plagued with these little buggers. Pay attention to you population of aphids. if you begin to see hard brown casings in and amongst them, this is a sure sign that you have a predatory wasp that eats the aphids. I was so happy when I discovered what those brown little dots on my mw plants were!

    I still rub out and spray with water. The wasps cannot get every one of them. I also have a really healthy number of lady bugs that mate and lay eggs over and over in my garden every year. Hoverfly and green lacewings also eat the aphids. Happy Hunting!

  6. says

    I bought a pair of tweezers specifically for removing these milkweed aphids from my Narrow Leaf Milkweed plants. I pick them off a few at a time and place them in a cup of water. They are surprisingly easy to pick off the plant – they don’t make any attempt to run away. If you have only a few plants and do this a few minutes each day, you can stop the infestations from getting too serious.

  7. Jacki says

    I’m in Oklahoma and the aphids are horrible. I mix a spray bottle with a couple of teaspoons of Dawn and fill the rest with water. Every morning, I spray the aphids and they’re dead by afternoon.
    I do have a new problem this year though. I have what I thought was a new variety of ladybug, but noticed the new bugs were eating the leaves at a very quick rate. They’re different colors, from beige to yellow to orange. They have a roundish body, and a snout. They’re not a worm. They’re literally eating my butterfly weed like crazy. They fall off easy enough, but will climb right back up. The soap water does kill them. It’s more of a nuisance than anything, but I’m wondering if anyone knows what these new critters are. Any feedback is appreciated.

    • says

      Hi Jacki,

      glad to hear the dawn is working for you. Sounds like a quick, easy, and effective mix. The problem with spraying in the morning is that’s when monarchs usually lay their eggs…so hopefully you get them all soon so you can stop spraying.

      I’m not sure what the milkweed pest is you’re looking for, but try searching google images to see if you can figure it out:
      http://images.google.com/

      If you want to get rid of them permanently, try the old “Japanese beetle” remedy. carry around a cup/bucket of soap water and just flick them inside. You could also try planting other milkweed varieties. Milkweed diversification is a key to consistently attracting more monarchs.

    • says

      Please have a look at this website for your beetle – it might be Milkweed Leaf Beetle. I have these in SE Texas on my plants of Asclepias perennis and A. curassavica. I just pick them off, squish ‘em, and add to the soil. I have also seen them on wild plants of A. perennis. Good luck!

  8. Jacki says

    Tony, I’m in Oklahoma and this is the first year I’ve noticed the ‘tick’ looking buggers and now these beetles. My butterfly bush has two problems; yellowing leaves that are falling off and leaves that are turning purplish/black. We’ve had a lot of rain so far so I think the moisture has contributed to the yellowing of the leaves. I’ll try to figure out how to post a link when I have time to take a picture today.
    You’re full of information! Thank you for your continued feedback.

  9. Peter Hornby says

    The LA Times article you linked to in point (3) said that alcohol is lethal to monarch eggs and larvae

    • says

      Hi Peter…it is if you get it on them. Whenever your treating milkweed you should always remove any eggs or caterpillars first. After you’re done you can rinse or spray the plant with water.

  10. Shefali says

    Hello! I read that horticultural oil will work to get rid of the aphids. My concern is making sure that our caterpillars are safe and that the oil won’t harm them. Have you heard anything about this?

    Also, will the dish detergent harm the caterpillars and chrysalis? We have both on our milkweed right now so I’m hesitant to put anything on the plant right now for fear of killing both.

    Last question: We went on vacation for a week and when we came back we saw one of our chrysalis next to the milkweed pot. Is there any way to save it? Or is it dead? Any ideas on how it would have been removed from the plant? We’re so sad about it!

    TIA!

    • says

      Hi Tia,

      any potential substance like horticultural oil or insecticidal soap needs to be rinsed off before it is safe for monarch eggs and caterpillars. You can always try hanging up the chrysalis by tying dental floss around the cremaster (top black part) of the chrysalis. If it’s going to hatch, it should hatch soon. Good luck!

  11. Ginger Burns says

    Help!

    I live in coastal southern California and have had my orange flowering milkweed for 2 years. Last year I had several caterpillars that matured and became monarchs. Also had many eggs that produced caterpillars but then the babies started to disappear. This year my plants are bigger and healthy looking with many flowers but no caterpillars. My neighbor had so many that they ate her plants to the bare stems.. She brought over 5 small to medium caterpillars and put them on my plants, they too disappeared after a day or so. Two days ago she put 8 more on my plants, 2 large and a mixture of medium and small. Today the large ones were gone and I assumed they were went off to find the ‘hanging’ spot to become monarchs. I found a “dead one” on underside of a leaf and no others. Eggs have been laid over last several months but nothing hatches.

    There something wrong either with my plants or soil. I do have some assylum and weeds growing at base of plants and there is a scattering of bark covering the soil. Plants are in full sun and are lightly watered once a week. I have noticed that the leaves on my plants are narrower than my neighbors but nothing else. I do use a smattering of flower fertilizer once a year but do not use insecticides. I’ve had aphids both years but this year they disappeared quickly with no intervention on my part. Any suggestions as to what the problem could be would be welcome.

    • says

      You may be having an issue with predators. Wasps, ants, spiders, stink bugs, lizards… If you think there is an issue with your soil, check with a local university to see if they do soil testing. They can analyze your soil, then give you specific suggestions to improve the quality.

      However, since you were successful with these plants last season, predators sounds like a more likely scenario…

  12. Ginny Reeves says

    I raise monarchs and have been pretty successful here in Houston but this year the aphids on the milkweed are insatiable. The first year we were plagued by wasps that ate our cats. I cut down the low hanging fronds on our palm trees (where the wasps were keeping house) and so that problem was gone. I also built a “nursery” where I keep the cats that is bug proof. So far this year I have released 50 beautiful monarchs. My problem is keeping a good supply of milkweed and the ever present “black death” of some cats. Has anyone come up with a reason for the “black death”? Is it the soil, is it the milkweed, what the heck is causing this?

    • says

      Hi Ginny, black death is caused by the NPV virus or a bacteria. This is more likely to occur if you cage has excess condensation. In a humid region like Houston, I can imagine you have to keep a closer eye on this. If you are interested in learning about the process I use for a 95% survival rate, you might be interested in Raise the Migration 2 starting in August

  13. Jacki Snider says

    Hi Tony, I’m back with a question. I found my first Monarch cat and eggs today on my butterfly weed. I have been plagued with aphids and have been diligent to spray them nightly with a soap mixture. They’re still there and have taken over! Now that I know I have eggs and cats, is it safe to spray with my soap mixture? I’m harvesting the eggs and cats as soon as I see them (we have tachinid fly issues here), but really need to spray the aphids

    • says

      Hi Jacki, as long as the soap is thoroughly rinsed off the milkweed leaves, it shouldn’t harm your caterpillars. Milkweed diversification and having several patches spread around your yard/garden is one of the best ways to “naturally” deter them. As your garden evolves, hopefully more of the aphids predators start to patrol it. I hope you are able to rescue lots of monarchs from those flies!

      • Jacki Snider says

        Thanks Tony. We are growing and expanding our garden and hope that next year it will help considerably. We have two 5 day old cats and 10 eggs. I’m sure we have a lot more but I haven’t found them yet. It’s been raining a lot and I haven’t been able to investigate the plants.

  14. Stacey says

    I always use a fireplace lighter to sizzle aphids. I started doing this on my hibiscus years ago. If you wave the lighter back and forth quickly, it doesn’t hurt the plant. Of course, you will want to remove any eggs or cats first. Then, I spray them with water. The aphids fall off and I have made sure I haven’t started a fire.

  15. Chris says

    I just found a cluster of these pests on one of my swamp milkweed plants this past weekend. I filled up a spray bottle with water, adjusted the nozzle to stream and blasted them off the plant while gently holding it. It worked. Bye bye aphids!

  16. says

    At the risk of sounding like a contrarian, I I have confess that I never ever worry about my aphids on milkweed.

    Milkweed grows pretty rampantly. Especially the common milkweed, asclepias syriaca.

    You note that the aphids can dampen the seed production of milkweed — I have to admit I see that as sort of a system of checks and balances. Since common milkweed also spreads underground, I don’t really need more seeds. In fact, this plant can sometimes be a real thug and will take over an entire landscape/garden.

    It is such a valuable plant to monarchs, that I prize it regardless. But I don’t mind if there are fewer seeds. I grow other things for other kinds of wildlife, so I don’t want to become a milkweed seed factory.

    Soaps and oils can harm the monarchs, and I also kind of trust the ecosystem to do its thing with this one.

    So I just leave the aphids and consider them part of the color of my garden.

    Most years I have had many many monarch caterpillars. Last year was a bad year region-wide — monarch numbers were down everywhere. And interestingly, I didn’t have many aphids last year or monarchs. But when the monarchs are good and the numbers are high, they do not seem to be bothered by the aphids.

    I suspect that there’s a relationship going on with the aphids, monarch caterpillars and the plants that may actually be productive or beneficial. If I find some data on that I’ll post it here and on my own blog. In the meantime, I do not like to treat any of my plants in any way.

    This is a great website and I love to see others encourage monarchs and milkweed. That is something we all should be doing! Keep up the good work.

    • says

      Hi Alison, I don’t typically worry about aphids either. We have lots of milkweed and the predators take care of most of them. But for those that have smaller butterfly gardens and a limited milkweed supply they can be an issue. I regularly get comments and emails from gardeners about how to treat them so I wrote this post so people would know their options. One thing I’ve come to understand over the past few years is that there’s not a “one-size-fits-all” solution for creating a monarch butterfly garden. I agree that treating plants with any soaps/chemicals in a butterfly garden is usually not the best idea, and should be considered as a last resort.

      BTW- aphids are typically a bigger problem with species like swamp and tropical.

  17. says

    I just checked my milkweed and found no leaves, no seeds but lots of those little orange critters all up and down the stalks…aaaargh. I just planted it this year in the hopes of growing a new habitat for the monarchs. Fortunately the little critters haven’t found the frier milkweed on the other side of the barn. I haven’t checked the plants down by the stream yet. I will definitely check earlier next year to make sure that nobody is enjoying the milkweed except the monarchs…

    • says

      Hi Virginia, aphids and monarchs can coexist on milkweed, but you’re not likely to get eggs during an aphid infestation. Catching aphids at the beginning is key to stopping them. However, sometimes predators will step in and take care of the problem for you. If you pick 1-2 plants to protect next season that’s more manageable than the whole garden. I still hope you get some monarchs this season, Tony

  18. Craig Popov says

    Hi Tony, I live in South/Mid Florida and am building a butterfly garden and am having a bit of an aphid problem and was reading your notes here and you mentioned using several cultivars of milkweeds,, SO please advise which might be the best for this area. I so far have 6 plants which are all Scarlet. Two weeks ago I had 8 cats that were doing well and I was going to take them in and the next morning- ALL GONE- maybe Blue Jays?
    Now plants are recovering but are COVERED with aphids- I ordered a small amount of lady bugs
    and that might help, but would like to get other varieties of the plants too!

    Thanks,
    Craig

    • says

      Hi Craig,

      sorry to hear about your aphids. Milkweed diversification is a good way to make sure you always have some viable milkweed for your monarchs. Check out my resource page that lists 18 different milkweed and what regions they are native to. there are also non-native varieties that can be grown across most of North America:

      18 Different Milkweed Varieties

    • says

      Hi Craig, also wanted to comment on your missing cats. There are a TON of monarch predators that seem to have adapted to the toxins in milkweed. It’s impossible to stop them all. Since only 1-5% survive outdoors, my best advice is to raise a few indoors where you can raise with over a 90% survival rate if you have a good system in place.

  19. Ginger Hand says

    Hi. I contacted you a few days ago about this pest, and find that the alcohol really works. Each day since Sunday I’ve been checking the 2 Swamp Milkweed plants that I have, and am down to just a small number each time – but they keep coming! (Maybe they don’t realize that their free happy hour is deadly!) But today I noticed a white residue on the leaves and pods that had been covered with the aphids. Could this be a fungus, or could it possibly be a result of the alcohol on them? I haven’t seen any butterfly eggs yet, but have a few monarchs that visit.

    • says

      Hi Ginger, perhaps alcohol residue left on the plants + the sun is burning the leaves and pods? Overfertilization can also cause leaves to turn white. Funguses are often caused by overwatering. Swamp usually starts to look a little worse for wear this time of year, though ours has responded well to all the rain. The best advice I can give you (without knowing for sure what the problem is) is to remove the affected leaves and pods.

  20. Miss R says

    I tried spraying my plants with DEET to possibly kill aphids and prevent further infestation. It seemed to kill some, but now especially my milkweed looks worse and downright awful. Should I just leave it alone?

    • says

      While DEET may kill aphids on your milkweed, it’s also going to kill monarch eggs and caterpillars. If you want to attract butterflies and pollinators, an “organic” approach is essential to your success. Native milkweed typically looks pretty bad by the end of the season, so your milkweed may be at the end of its growth cycle.

  21. Melanie says

    I work in landscaping at a 5-diamond resort, so of course Aphids are a big no-no. Best way I’ve gotten rid of them (along with spider mites) is to just hose them off. It is very beneficial to cut off parts of the plant that has more infestation, then you can hose off the rest. Definitely keep an eye on your plants so you can catch them early! :)

    • says

      Thanks for sharing your experience Melanie. Many times in home gardens (where you have the luxury of letting things play out a little longer) aphid predators will take care of the problem. We have been aphid-free the past few years without intervention, but have started to see a mini-infestation on our milkweed as this season nears the end. I did end up cutting back a few areas of heavier infestation, and now the ladybugs are taking care of the rest…

  22. Brett Budach says

    I think we need to make some things more clear for the readers. Someone I know just told me they interpreted the use of alcohol to mean that it was harmless to the Monarchs and only damaged the aphids. This could obviously lead to some horrendous mistakes in an aphid-infested garden. That was obviously a ridiculous mistake on their part, but it seems worth noting on this page that the LA Times article does say that it will kill the Monarchs, and must be used on a cottonball to dab only the aphids.

    • says

      Thanks for the suggestion Brett. It actually does say that alcohol is lethal to monarchs in the LA times article, but I added a block quote under #3 for clarification. Also, I use cotton swabs…it’s easier to access small spaces.

  23. Karen Murray Joss says

    I raise my cats inside a “butterfly house”. A netted place where I put my cats & plants. I have found that I must keep about 20 plants in pots covered with popup laundry hampers to use as the cats eat up what is in there enclosure. I have raised and released over 60 monarchs this year. I trim back the eaten up plants and regrow. When I find 1st or 2nd instar I use a fine artist brush to transfer them to the butterfly house.
    I also raise zebras this way as the are very slow growing and the anoles get them.
    For aphids I use a different brush to paint the aphids and then rinse with water; or just squish them. Very few butterflyies in my garden now – is it the heat? I live in SW Florida. I can keep my plants going all year.

    • says

      Hi Karen, a brush sounds like a good idea for scarping away aphids too…and easier to get in the nooks and crannies as opposed to with your fingers. Now that September is upon us, it will start to cool up north bringing more butterflies your way. Enjoy!

  24. Mitz Oates says

    I was in Wis for a week and gathered some milk weed seeds and hope they spout. When I returned to Florida I had lots of cats on my outdoor plants. I had to leave for TX the next day for 4 days and when I got back I could not find one cat…I think I have maybe one egg. What would get to the cats so quickly? Now my plants are 2 1/2 feet or so. Should I cut them down and let them start new once they go to seed?

    • says

      Hi Mitz,

      in Florida I would cut back plants one or twice a year to avoid build up of disease spores on overused plants. I would try to cut back during periods when there are typically less monarchs in your area.

      You also have more predators than the rest of us including lizards. There are many monarch predators that can wipe out your patch pretty quickly. Ants, spiders, wasps to name a few.

  25. Kelly Lowe says

    Hi Tony! We have milkweed growing in our school garden, and it’s infested with aphids! I was wondering if you could recommend a good companion plant to plant alongside the milkweed in their bed? Thanks so much! Great info here!! -Kelly

    • says

      Hi Kelly, I’ve heard of people using companion plants for aphid control but I’m not sure how well this actually works. We haven’t had a serious infestation in 3 years, but that’s (probably) because I’ve allowed our local ecosystem to develop that includes aphids AND the predators which include ladybugs and lacewings.

      Another strategy is to diversify your milkweed varieties and have several patches spread out if space allows. There are many options to choose from:

      18+ Milkweed Varieties

      If you’d like to try companion plants, marigolds and ‘summer beauty’ allium are “supposed” to repel aphids…they also attract butterflies…especially the allium. Please let us know how it works for the aphids…

  26. Kathy Gleason says

    Hi Tony,

    After taking an adult education class on populating monarch’s, I’m hooked. I have two potted milkweed plants which have been inside my home. I move them outside during the day in hopes of attracting more monarchs.

    I hatched my first monarch, which was released into the wild. This same monarch flew back here after a week or so to the same milkweed plant where it was born to lay it’s egg. Pretty cool, huh? Problem was I was, at that time, I was seeing aphids on these plants but was too afraid to treat and now both of my plants are in bad condition. The good news is I have SEVEN very healthy caterpillars who are unaware of my aphid problem and are just chomping away. They will be eventually running out of milkweed. My question is this: I am going to get new milkweed so all seven caterpillars will have plenty to eat. So that my new plants don’t get infested, is it okay to literally remove the caterpillars by hand onto the new plant? Do I need gloves? Will this harm the caterpillars? I think by leaving the new plant next to the old plant and waiting for the caterpillars to eventually move to the new plants, I risk the aphids invading the new plant as well. I also want to treat the infested plants as quickly as possible by cutting them back, treating organically, and seeing if I can regrow back into healthy condition. Any other advise will be greatly appreciated. Thanks very much.

    • says

      Hi Kathy, congrats on your exciting new hobby! Aphids are a common issue for most of us and can be very frustrating if you have a large infestation. They don’t hurt monarchs, but they suck the sap out of the milkweed and plant health will deteriorate. An infested plant will also not typically receive monarch eggs.

      As for handling caterpillars, you can gently pick them up between your thumb and forefinger. As long as you don’t squeeze or pull them too hard, you won’t hurt them. They’ll probably curl up into a ball, but that’s just their natural (and not very effective) defense.

      If you want to learn my system for raising indoors, my raising guide outlines the process I use to consistently raise monarchs with a 95% survival rate.

      Monarch Raising Guide

  27. Christi says

    Hello, I am new to planting and managing milkweed plants and their aphids. I have just planted my seeds and I’m hoping for the best. I have had success eliminating aphids on other plants by using pure essential oils (mostly lemon and lavender) mixed with water in a spray bottle. I didn’t read through all of the comments but have you ever tried or heard of anyone trying this with the milkweed? I don’t know the effects on the caterpillars. It shouldn’t hurt them if the oil is certified pure therapeutic oil… the kind that is safe to ingest. I read on a few comments that soap keeps them from attaching chrysalis? Not sure if the oil would have an issue. Since this oil is pure, and contains no synthetic material, it soaks into human skin and leaves no residue so should have a similar effect with plants.

    • says

      Hi Christi, I don’t suggest putting any substance on milkweed and leaving it there. Monarch females test milkweed with their feet, and if there is a substance on the milkweed they will probably bypass it. You could try spraying just a couple to see if you get any eggs, but I would try some of the ideas in the post if you are having aphid issues. good luck!

  28. Ann says

    Hi, Tony. Thanks for the much needed information posted here. I’m a new milkweed enthusiast. I live in CT. Last summer I purchased from a local nursery an Asclepias incarnata ‘Ice Ballet’ milkweed. Within a few days it was covered from top to bottom, leaves to stems, with aphids. I suppose they came with the plant! The leaves turned yellow and dropped off…as if the plant was dying.
    I did some research and chose to spray the plant with dish soap and water. I was trying to keep the plant alive! I was warned the aphids would spread to the rest of my garden. The spraying wasn’t effective. In desperation, I cut the plant right down in hopes it would regrow this year. It’s still cool here. Think there’s any hope?

    • says

      Hi Ann, if the milkweed had a good root system it should come back even if you cut it back to the ground. It is still early, and our milkweed patches in Minnesota are still lifeless too. I would give them a little more time before looking for alternative plants. Good luck!

  29. Elaine Gunderson says

    I live west of Edmonton Alberta zone 3. Was wondering what type of milkweed would I be able to plant. We need to attract more butterflies here.

  30. Sheila Rayburn says

    do you know what insect/ butterfly lays dark grey ovoid eggs? These eggs have the same shape & ridges as the monarch eggs; but they are very dark grey. Thanks for any help.

    • says

      Hi Sheila, the monarch eggs turn dark on top before hatching (actually the caterpillar’s head). If the whole egg turns dark it can signal a disease issue and the egg won’t hatch. The queen butterfly (Danaus gilippus) is also a milkweed butterfly that has stages similar to monarch development. You might trying keeping the eggs and see what develops. good luck!

  31. says

    In order to avoid large infestations of aphids throughout my garden, I have found it useful to take nature’s example and grow milkweeds in a matrix of other native flowers and low native grasses. I still wind up with other things that consume the milkweed (aphids, bugs, beetles), but frankly, they are all part of the diversity I want to attract by growing native plants. Milkweeds support monarch butterflies, but they are also important for a lot of other specialist insects, which may not be as pretty, but are nonetheless just as tied into the ecology as the monarchs.

    • says

      Thanks for posting Dan. Over the past few years I’ve come around to your way of thinking. We have an established garden and grow 16 varieties of milkweed so I try to support the entire local ecosystem…we even let a paper wasp nest stay this season. For those with less established gardens and a limited supply of milkweed, it’s more difficult to sit back and watch your milkweed be decimated by uninvited pests…you could always go to a store and buy more plants, but some are on a limited budget and, worse yet, it can be difficult to find milkweed plants that have not been treated by monarch-killing pesticides.

      A good long-term goal for those that want to support monarchs (in harmony with the local ecosystem) is growing 3-4 milkweed varieties and spacing them out around your yard and garden. This insures you’ll always have some viable milkweed in your garden when the monarchs unexpectedly drop in…

  32. annep says

    I planted ten common milkweed in my tiny garden last
    year this year they have come up in a very healthy way and I think I planted them too close together. Do milkweeds mind having no space between them. For sure they don’t grow that close together in southern ontario. how do they take to transplanting?

    • says

      Hi Anne,

      Our common patch is probably our only patch that isn’t spaced out. If plants are crowding each other I usually pull one and discard or transplant. Transplanting is best done in early spring before the plants reach 6″ tall and there is too much foliage…larger transplants would need to be cut back so they can focus on root growth…you can also transplant in fall.

  33. Heidi Stuart says

    HELP! I have been a fan of monarch butterflies for 40 + years. Last year I hatched and shared over 100 from my yard. In order to have fresh milkweed later in the season, I started systematically pulling older plants (always checking them for eggs before discarding them). The young plants that then grew had heavy aphid infestation. Late in the season, I found this site and tried squishing the beasties, cutting the highly effective leaves, and even pulling young milkweed that was too heavily covered. Through these methods, I was able to get enough to feed my caterpillars, but had to send some of the people I gave eggs and caterpillars to out searching ditch banks and roadsides.

    This year the milkweed plants have not grown back in areas that have had many plants before. Also, some of the milkweed has grown back with wavy, thick leaves.

    I brought three eggs in this morning, and want to continue to raise monarchs, but I am afraid I will not be able to feed them. I am willing to buy milkweed plants but don’t want to subject them to the same fate. Do you have any advice?

    Thanks,
    Monarch1fan

    • says

      Hi Heidi, it seems strange that perennial milkweed would disappear in areas it was growing before…especially if you are letting it seed. It sounds like your plants could potentially have a bacterial or viral issue. I would suggest amending the soil with compost and cutting back affected leaves to see if new growth improves. If more plants don’t come back, consider trying a different milkweed variety or other butterfly plants in those regions. I would also suggest trying to establish a good supply of healthy milkweed before you get back to raising more monarchs. Good luck and keep us posted…

  34. Joan Maffei says

    Hi Tony,
    I collected eggs and larvae from my yard and raised them in enclosures on my porch. I was able to release about 50 Monarchs in Central Texas in late May. I thought the Monarchs had left my area and so did not cut back the tropical milkweed in my yard. Today I found at least four big, healthy larvae on the MW. Now I’m worried that I should have cut the MW back as soon as the first bunch left on their journey North. Have I prevented late developing Monarchs from migrating and/or contributed to the OE epidemic?
    Thanks for all your great help with the Monarchs,
    Joan Maffei

    • says

      Hi Joan, it’s really hard to say what your late Texas monarchs will do. The only way you’d ever know is if they were digitally tagged so you could monitor their movement. All you can do now is raise and release them and let nature do the rest. After they’re finished would be a good time to cut down all your milkweed so healthy growth can emerge. Good luck!

  35. Nancee says

    My personal favorite is smooshing with forefinger and thumb (permanent stain throughout Monarch season) and then blasting them off with the hose. (Very good therapy)
    But watching you vacuuming them off is possibly the funniest darn thing I’ve seen for a while. Considering we both have a large quantity of plants, and all infested with aphids, I think I may have to hire the Merry Maids to help!

    Love your post!

    • says

      Nancee, someone from your region emailed me and said they went out to vacuum all their aphids after reading this…and it worked beautifully!

      For a large infestation, that’s probably what I would try, but ladybugs and lacewings have really been good to us over the past few seasons…

  36. Marie says

    I purchased one milkweed native to S. Africa (Gomphocarpus physocarpus, Balloon Plant Milkweed) back in March and it came with a caterpillar which became a Monarch butterfly. We released it and I was then hooked on Monarchs. I planted the plant which looked ragged but it became a nice, almost 4′ bush. Last week I doused it with an enviro friendly insecticide because it was infested with aphids. However since the aphids were not affected, the next day I started spraying the plant with 2tsp soap to16oz water. To my horror I saw a tiny caterpillar so I stopped. I then checked every leaf which looked like it was chewed and rescued about 5 tiny cats. I placed them on a plate inside the house with milkweed leaves. I continued “soaping” the plant and after an hour I hosed off the entire plant using my hand to support every branch. 15 minutes later I put the cats back on the plant. I noticed several tiny eggs so I will not spray the bush anymore but instead, once a day, I use a cotton swab to rub off the aphids. It works well and the aphids are under control. There are still some on the plant but not as many as before which must have been in the hundreds. I am amazed to have at least 15 cats now on the plant. I have never seen a Monarch butterfly in my neighborhood before so this is truly special. I will continue to plant more milkweeds primarily native ones. My goal is to establish plants that will help pollinators in general but right now I am focused on Monarchs just because of all the cats on my one plant. Your website has been one of the best informational website on these butterflies. Thank you.

    • says

      Hi Marie, I’m glad you were able to rescue the monarchs…spraying soaps or pesticides in the garden can work, but should be more of a last resort…too many possible unintentional consequences. I hope your monarchs will be OK on the treated plant. I would encourage you to try safer options from the post if that doesn’t work out…good luck!

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