Asclepias stenophylla (Narrow-leaved Milkweed)

Plant Info
Also known as: Slimleaf Milkweed
Family:Apocynaceae (Dogbane)
Life cycle:perennial
  • State Endangered
Habitat:sun; dry hill prairies
Bloom season:June - August
Plant height:1 to 2 feet
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 5-petals Cluster type: round

[photo of flower] Round clusters of 10 to 15 flowers each arise from leaf axils in the upper part of the plant. Individual flowers are about ¼ inch long, pale greenish white with 5 flaring petals and a 5-parted crown. The horns are mostly absent, or barely longer than the hoods in the crown.

Leaves and stem: Leaf attachment: alternate Leaf attachment: opposite Leaf type: simple

[photo of leaves] Leaves are 2 to 6 inches long and very narrow, less than ¼ inch wide, typically folded lengthwise, with little or no leaf stalk and tapering to a fine point at the tip. Attachment is mostly alternate, nearly opposite, and widely spaced. The main stem is green to purplish and unbranched. Stems and leaves are hairless to slightly hairy.


The most spidery of Minnesota's native milkweeds it could be more difficult to spot but for its austere habitat preference. Few-flowered umbels and long thread-like leaves present a delicate profile. A difficult task to find but for direct info on Minnesota's only known location—we walked right up to them. The steepness of the goat prairie and other attending flora in bloom, along with the breath-taking drop of the horizon into verdant valleys below, made for a spectabulus day. According to the DNR, the one known population of Narrow-leaved Milkweed in MN may have migrated here from natural species dispersion, rather than a remnant population from times past. It was added to the State Endangered List in 1984.

Narrow-leaved Milkweed somewhat resembles Green Milkweed (Asclepias viridiflora), which can also have linear leaves but they are broader and its flowers are more green to purple-tinged, with petals that do not flare much if at all.

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More photos

Photos by K. Chayka and Peter M. Dziuk taken in Houston County.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Christine - Douglas county
on: 2017-08-01 12:58:02

I found some flowers along the Central Lakes Trail just east of Alexandria. I didn't realize that it was a narrow leaved milkweed until I got home. I feel terrible about not realizing what it was sooner! Never expected to find a rare plant along the side of a bike path! I have to go back and see if I can find back.

Posted by: Christine d - Douglas county
on: 2017-08-02 13:55:37

Not sure if what I found yesterday really was a milkweed or not.

Posted by: K. Chayka
on: 2017-08-04 17:42:53

Christine, if you check the county distribution map, you'll see that Asclepias stenophylla is only found in a single location in Houston County, found on a dry goat prairie. It is pretty unlikely you'd find it in the Alexandria area.

Posted by: Nick Smith - Garfield
on: 2019-06-18 00:43:13

Believe she right in Douglas county cause Garfield has it I feed it to my rabbit good for my dog and the rabbits are my dog food after all the poisonous marketing of today's world of food for use human and animal.. tell me how I can multiply that milkweed I believe glad to do so, didn't no that it was on endangered species list

Posted by: K. Chayka
on: 2019-06-20 18:40:25

Nick, I have to question whether you have the correct ID, or if so, whether it's a natural population. If you have images post them on our Facebook page and we'll see if we can confirm. In any case, chances are it is green milkweed, Asclepias viridiflora.

Posted by: Isabel C. - Cannon Falls
on: 2021-07-27 17:27:31

I found it on a roadside. And last year it grew in a Prairie restoration habitat close to Lake Bilsby. I will try to collect a couple seed pods in a week or two. I hope I can spread its seeds and help it a bit.

Posted by: K. Chayka
on: 2021-07-28 18:43:03

Isabel, it seems unlikely you would find this rare species on a random roadside. It is possible it could be in a restoration seed mix, but I thought including rare species like this in such seed mixes was frowned upon. Are you sure it isn't a different milkweed, possibly whorled milkweed?

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