How to harvest milkweed seeds: A tutorial

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Milkweed seed pods
Milkweed seed pods naturally expelling seeds (Tami Gingrich photo)

I don’t know about you, but this was the most disappointing summer for monarch butterflies here in northeast Ohio that I can remember. The total number of adults I spotted could be counted on just one hand. The milkweed plants in my pollinator garden, both common and swamp, were lush and vigorous (partly due to lots of watering), yet, they hosted not a single monarch caterpillar. Suffice it to say, something is very wrong.

In 1975, the monarchs’ overwintering sites in the mountains of Mexico were discovered, leading to intense studies of their population dynamics. Sadly, in just the past 20 years, their population has plummeted by 90%, leading scientists to predict an almost inevitable extinction of the migratory faction. There are many contributing factors playing into this decline including climate change, loss of overwintering site habitat due to logging and, most importantly, the absence of the one and only plant on which their larvae depend for sustenance — milkweed.

Milkweed decline

swamp milkweed
Small, slender swamp milkweed pods (Tami Gingrich photo)

Patches of milkweed, once common and vigorous, have been eliminated by aggressive applications of herbicides along roads, pastures and croplands. One of the most customary areas where common milkweed persisted profusely was in and around the edges of agricultural fields. These plentiful patches provided monarchs with safe havens where they could lay their eggs and fuel up on nectar. Yet, with the invention of genetically modified crops, corn and soybeans are now tolerant to herbicides, allowing the farmer to spray them directly with glyphosate resulting in no ill effects. While the crop itself remains unscathed, all other plants between the rows and around the edges of the fields are wiped out, saving the farmer valuable time which would otherwise be taken up by tilling. According to the University of Kansas’ Monarch Watch; “Widespread adoption of herbicide-resistant corn and soybeans has resulted in the loss of more than 100 million acres of monarch habitat in recent years.”

Having been involved with monarch butterflies most of my life, I feel a desperate calling to do everything in my power to help this iconic insect. During my tenure at the park district, I initiated a project to grow native milkweed plants in pots to distribute to the public. My annual “Mother’s Day Milkweed Giveaway” became an overwhelmingly popular event and I was able to distribute thousands of plants yearly that would be lovingly planted and cared for, all in the name of monarchs. Since my retirement 4 years ago, I have transitioned into a volunteer capacity and continue this project even more fervently than before. I am grateful for the greenhouse space given to me by a local garden center (John’s Country Nursery) that allows for the success of this operation.

Propagating milkweed

yellowing milkweed leaves
Yellowing leaves on a milkweed plant is an indicator of mature seed pods. (Tami Gingrich photo)

Propagating milkweed is actually quite easy and the time to harvest the seeds here in northeast Ohio is right now. There are many species of milkweed found across the United States, each specific to its particular region. Here in northeast Ohio, the two most common species are common milkweed (Asclepias syriaca) and swamp milkweed (Asclepias incarnata). Common milkweed, with its broad leaves, can be found growing along roadways and fence lines, while swamp milkweed flourishes around ponds, lakes and moist areas. In late summer, green seed pods become visible, evidence that the pollinators that visited the plants’ vibrant pink blossoms successfully accomplished their job. These pods contain seeds, each equipped with its own flossy parachute that allows it to sail far and away to establish new patches in supporting habitat. As the seed pods mature, a built-in zipper along the side, pops open, allowing for the parachutes to slowly emerge and be carried off by the breezes.

If you would like to try your hand at harvesting some milkweed seeds, do so before the pods open and begin releasing their contents. Trying to harvest seeds out of the flossy mass is incredibly time-consuming, messy and frustrating. Wait until you see the leaves of the milkweed turning yellow and falling from the stems. At this point, the pods will still be green. To determine if they are ready for harvest, pop open the zipper along the side and have a peek inside. If the seeds are brown, they are ready, if they are still white, leave them be for a while longer. You don’t need to pop open every pod. If the seeds in one or two are brown, you can assume that all of them in that particular patch are as well.

I keep a mental note of the patches where I will harvest — those that have the largest, healthiest pods. Gently pull the pods until they separate from the stem and place them in a paper bag. I am always mindful to leave pods here and there as I collect, so as not to decimate the seed bank for that location. Once you have your desired number of pods, you are ready to go to work. Don’t let them sit in the bags for too many days or they will dry and begin to open, defeating the purpose of collecting them early.

On a table with lots of room, grab a pod and pop it open along the zipper. Use your thumbs to widen it enough to reach a couple of fingers inside. Reach around the end opposite from the stem and pull the point up and out. This is where all the flossy parachutes come together, so with your fingers, get a good grip around the entire tip so that they don’t separate. If you are right-handed, grab the end with your left, or vice versa. Now, pull the entire contents out of the pod. The freed structure reminds me of a little fish, covered with brown scales. Continuing to hold tight the end, use your thumb and forefinger of the other hand to grasp around the structure, gently rubbing the scales free and allowing them to drop onto the table below. In just a matter of seconds, you will have the majority of the seeds freed with just the floss remaining. Throw the floss into a bag so that you can toss it out later into an area where any leftover seeds can have a chance to germinate. You can also save the empty pods. Once they dry, they can be used in fun art projects such as ornaments, wreathes etc.

You will find that, because of the milky substance from which the plant gets its name, this can become a sticky job, so you may have to wash your hands several times throughout the process. Once you have your seeds, spread them out on a newspaper and give them around a week to dry. If you simply plan to spread them in an area of your property, or in your garden, you should do that before winter sets in. Like many seeds, those of milkweed require cold stratification, a period of cold which helps to break the dormancy of the seeds so that they can germinate in the spring. To achieve this with my seeds, I put them in a plastic bag with a slightly damp paper towel and stick them in the refrigerator for at least three months. The following April, I pull them out and sow them shallowly in pots. Starting them this way ensures a much higher germination rate for the plants.

If you are a monarch butterfly fanatic such as I or simply want these beautiful plants in your pollinator garden, I hope this tutorial has been helpful. It has worked for me for decades with germination rates extremely high. Most of all, it will certainly be beneficial for the monarch butterflies who so desperately need our help right now, more than ever!

Video

milkweed plants
Tami Gingrich’s “Mother’s Day Milkweed Giveaway” for the Geauga Park District became a popular event that allowed her to distribute thousands of plants yearly. (Submitted photo)

To view a little video of this process, please visit my YouTube channel link youtu.be/Q6VZNQ4AVh8.

Also, if you don’t have access to common milkweed seeds, just let me know and I will be happy to put some in the mail to you.

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7 COMMENTS

  1. Thanks for sharing this! I was wondering what to do with them! My plants been struggling so hard this year.
    Could I please have some seeds?

  2. My wife teaches 2nd grade and every year we would collect a couple of monarch caterpillars to show the life cycle to her students. The kids all love the experience and older kids will even stop back in her room every day just to see how they are doing.
    This year we spend days searching for, not only caterpillars, but also milkweed itself! We would have to drive for 30 minutes each way just to get some food for our 2 little caterpillars that we did find. Luckily we have found over the years that you can wrap the leaves in wet paper towels and they can last in the fridge for a few days.
    We were thinking of growing the milkweed next year to hopefully attract butterflies and make things easier. Is it hard to grow them in pots? Hopefully we’ll be able to get out to get some seeds

  3. After reading your tutorial,I discovered I have been collecting milkweed seeds the wrong way,after the pods open.Please send some seeds to me.Locating monarch butterflies was a challenge this year.To date,I saw three.I would appreciate th seeds,
    as milkweed here along roadways is mowed down before it even gets a chance for me to pick.Thank you very much.I save all the articles I find of interest in a folder,too interesting not to keep.Take care.

  4. I have a huge garden in my backyard and it’s simply for monarch butterflies and hummingbirds. My garden is thriving with monarchs this year. The female monarchs kept coming to my garden to lay the eggs. And at meanwhile I provide the shelter for the caterpillars to grow to prevent the predators. In the month of July to now, I saw them pretty much every day. I still have more than 100 chrysalis waiting to hatch. I so glad I did something for our monarch butterflies. They need milkweeds, but also need flowers. Thank you for your detailed and very instructive article. It’s a very pleasant feeling to know that someone is caring for them. I harvested a lots of common milkweed seed and plan to grow even more milkweed by this coming winter. I also can provide milkweed seeds. If anyone needs it, please visit my Instagram page @ littlebirdinthebackyard and leave a message, I can send the seeds to you.

  5. I just harvested a huge amount of seeds from ripe green pods. They have grown naturally and have no herbicides or even fertilizer. I have many friends across the United States that I can send seeds. What is an amount of seeds to send. I probably have more than a cup of the seeds I harvested yesterday.

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