Prairie Milkweed for Monarch Butterflies
Asclepias sullivantii common names: Prairie milkweed, Sullivant’s milkweed
Prairie Milkweed Plant Specs
- Perennial Zone: USDA hardiness zones 3-7 (lows -40 °C or -40 °F)
- Native Plant: Central US and Eastern Canada ( Ar, Il, In, Ia, Ks, Mi, Mn, Mo, Ne, ND, SD, Oh, Ok, SD, Wi)
- Full sun to part shade
- Height: 2 to 3 feet
- Spacing: 1 to 2 ft
- Flowers: shades of pink to pinkish-purple with fragrant blooms
- Smooth leaves and seed pods compared to Common Milkweed
- Deep pink midbribs
- Green stem with pairs of opposite leaves
- Blooms during summer months (June, July, August)
Asclepias Sullivantii Pros
- Easier to control in a garden setting than Asclepias syriaca
- Popular host plant for caterpillars
- Many butterflies use as a late spring nectar source, including monarchs
- True prairie species that can withstand dry weather conditions
- Easy to start from milkweed seeds
- Sweet fragrant blossoms that fill the air
Asclepias Sullivantii Cons
- Seeding can be a problem unless you take actions below
- Prone to aphid pests like most milkweed
- Can spread through underground rhizomes
- Does not transplant well because of long taproot
Asclepias Sullivantii Plant Propagation
- Sow seeds directly outside in fall– November is a good option for most regions
- Start seeds indoors 2 months before final frost- seeds must be cold stratified
- Spring Sow seeds directly after final frost
- Winter sowing is a good option if you want to control plant placement in early spring
- high germination rate starting seeds in water
Prairie Milkweed Growing Tips
- Easiest to fall or winter sow
- Separate ‘prairie’ from other plants that could fall victim to an underground rhizome attack
- Cut I- If you don’t want additional seedlings next spring, simply cut off all/some of the seed pods before they pop open or cover them with organza bags if you want to collect prairie milkweed seeds
Prairie milkweed also attracts bumblebees, honey bees, milkweed bugs, various butterflies, moths, hummingbirds, and other pollinators
Buy Asclepias Sullivantii Plants and Seeds
Always purchase seeds and plants by botanical (scientific) name. Asclepias sullivantii’s common name, prairie milkweed, is also used to refer to other milkweed species:
- Buy Prairie Milkweed Plants or Seeds from Joyful Butterfly
- Find Prairie Milkweed on Etsy
- Buy Prairie Milkweed Seeds on eBay
Click here for 30 Milkweed Ideas for your Butterfly Garden
Please post below if you have any questions or comments about growing Asclepias sullivantii in your garden:
I’m seeing exactly the same caterpillar mortality on A. sullivantii that Linda reported. In addition to monarch caterpillars my plant also appears to be toxic to tussock moth caterpillars. In June dozens of tiny caterpillars hatched on one leaf. Within three days of hatching they were all dead.
hi Terry, we get a lot of eggs on our A. sullivantii but I’ve never used it for raising before, or noticed dead caterpillars outside. I will pay closer attention to see if we are having the same issue…
Concern about A. sullivantii: This species showed up in my prairie patch and the Monarch females seem to favor the tender leaves and loaded it with eggs. Problem is that a few of us experienced caterpillar rearers have seen that the hatchlings eat a small circle of it and then stall as if unable to feed further on the leaf. Unless they are transferred to Common or Swamp milkweed they do not thrive. Has anyone else noticed this? If so, it seems I don’t want A. sullivantii in my garden.
Hi Linda, I have never heard of any issues feeding caterpillars A. sullivantii. We have one plant in our garden. We received eggs on it, but I switched to common because we have a large supply.
Just getting started in Central Illinois in September. Plant seeds now?
Hi Kris, it’s usually best to wait until the ground is closer to freezing toward November. here’s more info:
Fall Planting Milkweed Seeds
I’m in Urbana, Illinois and starting to grow incarnata (2 plants) and sullivantii (2 plants) which I obtained from a local group called Grand Prairie Friends. We’ve had good summer weather with lots of sun and several heavy rains. Although the plants in each pair began at the same size (the sullivantiis were much bigger than the incarnatas), they grew at quite different rates. I note that they are top heavy and their trunks are bare up to a certain point. Heavy rains made the tallest one lean way over, so I’ve staked it. Is this a good idea? My biggest problem is no eggs. If the monarchs don’t discover my plants, how can I get eggs? I’m also worried about whether the plants will make it through the winter. I planted a couple milkweed plants I got at a Monarch information gathering last July, and they didn’t come up this spring.
Hi Jim, swamp and prairie milkweed are both hardy to your region so I wouldn’t worry about them coming back next spring. You can stalk plants, but I would probably just cut them back a little. either way works. If you can’t find eggs or caterpillars, here are a few suggested vendors that sell them. I hope you are able to find some on your milkweed though!
Monarch Eggs & Caterpillars
I didn’t realize there were so many varieties of milkweed! Common Milkweed grows “wild” in my area (Northeastern PA) – however some descriptions don’t suggest it for this area.
I am planting other milkweeds – but really love the aroma of Common Milkweed…..will it grow here? Seems like a dumb question since I have seen it in the area….
Hi Kathy, common milkweed is native to your region, so I would definitely give it a try. You’re a bit late for planting seeds, because the seeds need cold moist stratification for at least a month. However, you might check out local nurseries or plant sales. Here are a few suggested milkweed stores that ship, with more plant options below:
Suggested Milkweed Stores
This is the first time I have purchased milkweed seeds.
I bought 4 kinds and placed them in my refrigerator.
I put them in dirt and two of the four have sprouted.
I am trying to figure out how far apart to plant them once I they are big enough to move outside.
Also, I am planting some of these in southern Wisc and some in northern Illinois. I am confused now, if I have to replant every year or do they come back up in the spring?
Hi Monica, if the milkweed species are perennial to your region, you only have to plant once. Sulivantii plants should be spaced 1-2 feet apart for optimal growth…good luck with your new garden!
I am trying to grow common and praire milkwood in a way that it is easily transplantable and am wondering how long the taproot would be on a two year old plant. Any info on this?
Hi JD, it is possible to transplant milkweed with taproots. This should be done in early spring or fall so the transplant is less stressful for your plants. Check out this post for more details:
Transplant Native Milkweed
I bought some for this Spring’s annex to the butterfly garden from prairie nursery in Wisconsin. Thanks for the great info!!
you’re welcome Laura, and good luck with your new plants!
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