Caulophyllum thalictroides (Blue Cohosh)
| Also known as: | Pappoose-root, Squaw-root |
|---|---|
| Genus: | Caulophyllum |
| Family: | Berberidaceae (Barberry) |
| Life cycle: | perennial |
| Origin: | native |
| Habitat: | part shade, shade; moist, rich woods |
| Bloom season: | April - May |
| Plant height: | 1 to 4 feet |
| Wetland Indicator Status: | none |
| MN county distribution (click map to enlarge): |  |
| National distribution (click map to enlarge): |  |
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Detailed Information
Flower: 
![[photo of flowers]](/udata/r9ndp23q/pd/caulophyllum-thalictroides-6.jpg)
5 or more stalked flowers in 1 or more loose, branching clusters at the top of the stem. Individual flowers are about ½ inch across with 6 yellowish green petal-like sepals and 6 yellow stamens in a ring around the green center. The true petals are tiny (barely longer than the stamens), greenish, and sit between the sepals and stamens.
Leaves and stem:
![[photo of leaves]](/udata/r9ndp23q/green/blue-cohosh_0719_104110.jpg)
Leaves are 3 or 4 times compound in groups of 3, each leaflet to 2½ inches long and wide, toothless and hairless, with 2 to 5 pointed lobes and a short stalk. The base of the leaflet is rounded and often asymmetrical, especially on the lateral leaflets. Non-flowering plants have a single compound leaf, flowering plants have 2.
![[photo of stem]](/udata/r9ndp23q/green/caulophyllum-thalictroides-blue-cohosh_0601_095020.jpg)
Leaf and flowering stems are in a whorl at the top of the stem. Stems are erect, multiple from the base, hairless and light green but may be tinged purple or blue and often have a waxy bloom.
Fruit:
![[photo of fruit]](/udata/r9ndp23q/green/blue-cohosh_0719_104147.jpg)
Fruit is a green, berry-like seed, about 1/3 inch across, that ripens to a deep blue. The fruit is poisonous.
Notes:
Blue Cohosh leaves look similar to some other plants, in particular the Meadow Rues (Thalictrum species) but Blue Cohosh has much larger leaflets and the Meadow Rues lack the whorl of leaf and flower stalks at the top of the stem.
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More photos
Blue Cohosh plant
Blue Cohosh plants
Blue Cohosh plants
more flowersPhotos by K. Chayka taken at Wild River State Park, Chisago County. Other photos courtesy Peter M. Dziuk.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2013-08-31 21:33:59
I have a single blue cohosh plant growing amid sugar maple seedlings, red baneberry, and Canada mayflower in a vegetative area under mature sugar maples.
on: 2017-05-08 16:25:47
Lots of these growing on the forest floor of the Izaak Walton League, Breckenridge Chapter property. This mainly oak and basswood forest is on the bluff of the Mississippi River.
on: 2018-05-02 14:54:10
Have found these at Oxbow Park in Byron, MN!
on: 2018-05-07 07:28:45
We have a large natural patch of Blue Cohosh in our back yard which was heavily wooded until we removed the Buckthorn and some Box Elders. I am now worried that this patch is getting too much sun and will have to move it to a spot where there is more shade.
on: 2018-08-11 08:07:53
This plant appeared in the moist woods behind our lake cottage after the removal of buckthorn!
on: 2018-08-25 14:57:52
I just found a clump in our woods (heavily wooded bluff area overlooking St. Croix River), when clearing out some aggressive raspberry bushes and ground ivy (which was going to smother a walnut tree). Never seen it before and had to look it up!
on: 2018-08-30 18:36:49
Found a clump next to the driveway with about 5 berries-it was growing in a clump of maple seedlings. We live near a lake.
on: 2019-05-10 12:36:52
There is a film on blue cohosh stems that when you touch it with your finger it comes off. I cannot think of the botany term for this "film". please advise. thank you very much Rachel
on: 2019-05-10 16:20:58
glaucous?
on: 2019-09-02 20:23:29
These are plentiful on my farm. It’s about 30 acres of wooded and wetland. I just was out there today – 1 September 2018.
on: 2020-05-02 13:04:28
Many out now along with other earlier ephemerals.
on: 2020-08-19 15:31:00
A few plants are present on basswood, ironwood & burr oak forested lake lot west of Alexandria
on: 2020-09-12 23:32:19
There's a large patch on an embankment overlooking Rice Creek at the edge of Locke Park in Fridley.
on: 2021-05-03 18:23:32
All in full bloom for the year, very nice.