How and When to Harvest Milkweed Seeds


Milkweed is the sole food source for monarch butterfly caterpillars. Monarchs have greatly decreased in population over the years, primarily because of habitat loss. As fields and meadows have given way to parking lots and shopping centers, the places where milkweed grew naturally have started to disappear. Luckily, we as gardeners can play an important role in ensuring that monarchs have plenty of milkweed.

Here in Michigan, there are six types of native milkweed, all of which provide food for monarch caterpillars:

  • swamp milkweed (Asclepias incarnata)
  • butterfly weed (Asclepias tuberosa)
  • common milkweed (Asclepias syriaca)
  • whorled milkweed (Asclepias verticillata)
  • tall milkweed (Asclepias exaltata)
  • prairie milkweed (Asclepias sullivantii)

Most of these milkweeds are native throughout the state, with the exception of swamp and prairie milkweeds, which are native only to the southern part of the lower peninsula.

Finding Milkweed to Harvest

Milkweed grows naturally in meadows, fields, and ditches throughout the state. You can identify milkweed in three ways: via its flower, its foliage, and its seed pods. The blossoms range in color from light pink to purple, except in the case of butterfly weed, which has bright orange flowers. The foliage is shiny, alternating up and down the stem, with long, feather-shaped leaves. Depending on which variety of milkweed it is, these leaves may be large or fairly narrow. In any case, when the leaf is snapped, a white sap should be visible; this is what gives “milkweed” its name. Be careful, though — this sap is a skin irritant, and you definitely don’t want to rub it in your eyes!


As far as the seed pods, they usually start appearing here in Michigan in late summer. At first they are bright green and quite plump. They look like a weird, kind of spiny/bumpy fruit. As the season progresses, they’ll get a bit lighter in color, eventually turning a greenish-yellow. When they’re at this stage, they may start splitting, and that is when you know the seeds are ready to harvest. When you open the pod, the seeds should be dark brown. If they’re green or light brown, they’re not mature yet and won’t sprout when you plant them. I always look for signs of pods splitting, which is nature’s way of telling you that the seeds are ready. You might lose a few seeds this way as they’re blown away by the breeze, but believe me, there are plenty more inside the pod.


Please note that you should always ask permission before harvesting seeds from private land, and of course seeds should never be removed from state parks or national forests.

How to Harvest and Separate Milkweed Seeds

To harvest the seeds, simply pull the entire seed pod off of the plant. You can actually store it as is in a paper bag until you’re ready to plant, or you can go ahead and clean the seed now to make it easier to store (in a cool place – preferably a refrigerator, which keeps the seed at a constant cool temperature. Milkweed needs a period of cold stratification to germinate; the refrigerator storage will provide that.)

The trickiest part of the entire process of saving milkweed seeds is separating the dark brown seeds from all of the white fluff attached to them. This fluff is essential to the milkweed’s survival. It acts as almost a parachute, and when the wind blows, it carries the milkweed seeds further away because of that fluff attached to it, dispersing the seed over a wider area. But for seed collectors, it can be a bit of a pain.

Here’s how I do it.

Sometimes, especially if you’re just harvesting one pod and it’s begun to split but hasn’t completely exploded yet, you can simply pull the wad of fluff and seeds out, run your fingers down it, and easily separate the seeds that way. The seeds fall into a container or tabletop, and the wad of fluff stays in your hand. That’s what I was able to do for these pods. You can see how they’re all still pretty self-contained below.

milkweed seeds

If you have more than just a pod or two, or you just don’t want to risk making a mess (that fluff goes EVERYWHERE…) try this: open your seed pods and empty them, fluff and all, into a paper bag, small coffee can with a lid, or a jar. Close the container and give the whole thing a good, vigorous shake. You can even add a penny or two to the bag to help agitate the contents even more. What the shaking does is shake the seeds loose from the fluff. The heavier seeds will fall to the bottom of the bag or jar, leaving the lighter fluff at the top. So after a few good shakes, all you have to do is open your container, lift out the ball of fluff that is on top, and in the bottom, you’ll see your cleaned seeds.

(If you have a huge amount of seed to process, check out this contraption from Monarch Watch: a seed separating machine for milkweed.)

Storing Milkweed Seeds

As I mentioned above, it’s best to store milkweed seeds in a cool place, any my preference is the refrigerator. I like to store my seeds in paper envelopes, which are easy to label, or in jars if I have a lot of seed.

What To Do With Extra Seeds

Often, you only really need a seed or two, especially if you have a small garden, while a milkweed pod can yield dozens of seeds. If you find yourself with more seeds than you can use, here are a few ideas:

  • Offer them to gardening friends
  • Contact your local 4-H, garden clubs, or wildlife restoration nonprofits to see if they would like to take some off your hands
  • If you’re involved in any online gardening groups or forums, offer them as part of a seed trade or for a SASE for those who want some.
  • Store them in your fridge or freezer. They’ll keep, stored this way, for a very long time. If you decide you have room for more milkweed plants, you’ll already have cleaned seed on hand.

I hope this has been helpful. There is nothing quite like sitting out in your yard or garden and watching monarch butterflies fluttering around the milkweed you lovingly planted for them. These beautiful creatures need all the help we can give them, and, in exchange, we get flowers plus the joy of seeing them in our garden.

Best Spring Perennials for Michigan: Bergenia

These gorgeous plants are grown as much for their foliage, which forms a pretty little rosette, and their flowers. Blooming in shades of white, pink, red, and purple, held aloft on sturdy maroon stems, they are a unique addition to the spring garden.

Where to Plant Bergenia:

Bergenia grows best in full sun to partial shade, in moist, rich soil. It is a good idea to plant them in groups of three or more plants for a nice display of color. Plant them 10 to 20 inches apart.

Bergenia looks great at the front of a border or along a walkway. Even when it’s not blooming, the rosettes of shiny green leaves will give you something attractive to look at.

Growing Bergenia:

Bergenia are actually pretty carefree plants. Other than making sure to water properly while they’re getting established, they can be left pretty much on their own. You’ll want to deadhead them after bloom, and divide regularly (see section on propagating Bergenia, below) to keep the plants growing strong. Once established, Bergenia are fairly drought-resistant, though you will want to give them some water (an inch or so per week) during an extended hot, dry spell.

Bergenia Pests and Diseases:

The most common pests you’ll encounter when growing Bergenia are slugs. If you start noticing holes in the foliage, look underneath the leaves and near the soil surface for the slimy pests, and hand-pick regularly to remove them. You can also try sprinkling coffee grounds or crushed eggshells around your plants to deter the slugs.

Propagating Bergenia:

You can start bergenia from seed, but it doesn’t always grow true from seed. It is better to start with plants or (if you’re lucky) rhizome divisions from another gardener.

You can dig and divide Bergenia by cutting and transplanting extra rhizomes in other spots in the garden. When making divisions, just make sure that at least one leaf shoot is attached to each section. Bergenia should be divided every two to three years to maintain the plants’ vigor.

Good Partners for Bergenia:

Ferns and irises both provide nice contrasts to the round, shiny foliage of Bergenia. Other good companions include spring-blooming bulbs such as scilla, snowdrops, or crocus.

Russian Sage

Russian SagePerovskia

If you have a hot, dry area of your yard (don’t we all?) consider Russian Sage. It is a gorgeous, ethereal plant with silvery green, lacy foliage that is topped with spikes of lavender blue flowers from July until frost. Russian Sage grows up to four feet tall and three feet wide, though some varieties are more compact. This is one of those plants in my garden that I pretty much ignore, other than admiring it.

Hardiness: Russian Sage is a perennial that is hardy to zone 3.

Cultivation: Plant Russian Sage in full sun, in average to poor fertility soil, as long as it is well drained. Russian Sage can be planted at any time during the growing season.

Care: Russian sage is a very low-maintenance plant. Make sure they don’t dry out during their first season (but don’t overwater, either!) and after that they’re pretty tough plants. They don’t need to be fertilized or divided. The only care they need is that they should be cut back to 6 to 8 inches tall in early spring to promote bushy growth.

Propagation: Russian Sage is easily propagated by taking softwood cuttings in May or June. “Softwood” means the current year’s growth, before it gets hard and woody. The cuttings can either be kept indoors under lights or in a window, or outdoors in a sheltered spot. To take softwood cuttings of Russian Sage:

  1. Cut about 4 to 6 inches from the end of a stem, right below a leaf node.
  2. Remove any leaves from the bottom 2 inches or so of the stem.
  3. Dip cut end into rooting hormone.
  4. Plant in seed-starting mix (a combination of peat, perlite, and vermiculite-or buy a prepared mix from the store) in either flats or pots. Using a pencil, make a hole 1-2 inches deep, stick the end with the rooting hormone in, and firm the soil gently around the cutting.
  5. Water thoroughly.
  6. Cover the pot with a clear plastic bag, supported by sticks to keep it away from the cutting.
  7. Keep the soil moist, but not too wet. The cutting will root within a few weeks and can then be planted out in the garden.

Good companions for Russian Sage:

  • Black Eyed Susan
  • Butterfly Bush
  • Purple Coneflower
  • Agastache
  • Starflower

Summer Blooms: Black-Eyed Susan

In July and August, the cheerful golden blooms of Black-Eyed Susan grace the garden. But before we talk more about them, we need to get something figured out: which Black-Eyed Susan, exactly, do you have in your garden? There are two very different plants that are both commonly called “Black-Eyed Susans,” (one example of why those pesky botanical names are sometimes necessary to know!) and they have very different attributes. We grow both of them in our garden, so let’s take a look at each.

Black-Eyed Susan #1: Rudbeckia hirta

Rudbeckia hirta is a native biennial or short-lived perennial, depending upon conditions in your garden. It grows anywhere from one to two feet tall (sometimes taller) and spreads via seeds. Each plant is composed of a basal rosette of foliage, and flower stems, each with a single bloom, emerge from the rosette. R. hirta blooms in late summer to fall. It tolerates a wide range of conditions, from full sun (which will result in taller plants with more blooms) to partial shade. It is not overly choosy about soil, though it does best in well-drained loam. In our garden, they’re managing just fine in soil that is mostly clay that we have amended with a topdressing of shredded leaves each fall.

R. hirta can become somewhat invasive if it is happy in your garden. We’ve had seedlings popping up in the lawn and in sidewalk cracks, so that is something to keep in mind regarding this particular Black-Eyed Susan. Another thing to note about R. hirta is that its foliage is fuzzy:

The leaves show some serration, but, as you’ll see when we look at the “other” Black-Eyed Susan, the foliage is definitely different, and is possibly the easiest way to tell the difference between the two.


Black-Eyed Susan #2: Rudbeckia fulgida

The blooms above are from the second type of Black-Eyed Susan, Rudbeckia fulgida, which is also commonly known sometimes as “orange coneflower.” Pretty hard to tell the two apart just from looking at the blooms, isn’t it?

R. fulgida is a perennial that grows into clumps about three feet tall by three feet wide. It grows well in both full sun and partial shade, and, while it isn’t picky about soil, it does best in moist, well-drained soil. R. fulgida blooms in late summer, just like R. hirta. In fact, both are blooming in my garden right now, in early August.

R. fulgida spreads by seeds, and you can also divide the clumps (which can expand quite a lot over a few seasons!) to make new plants. It is not nearly as likely to become invasive as R. hirta is, so if you’re looking for a well-behaved, low maintenance Black-Eyed Susan, R. fulgida would be one to look for. How to tell it apart from its prolific cousin? Again, take a look at the leaves. Where R. hirta has fuzzy leaves, R. fulgida’s foliage is smooth, and shows more serration at the edges:

(As you can tell from the photo, R. fulgida is also more attractive to insects. The plant is still growing robustly, though, so I don’t worry about it.)

I hope this helps you tell the difference between the two, and helps you decide which is a better fit for your garden.

What to Plant with Black-Eyed Susan:

Several plants look great planted with Black-Eyed Susans (of either type!) They include:

  • Purple Coneflower (Echinacea purpurea)
  • Blazing Star (Liatris)
  • Garden Phlox (Phlox paniculata)
  • Daylilies
  • Annuals, such as zinnias, marigolds, sunflowers, and cosmos