Oenothera biennis (Common Evening Primrose)

Plant Info
Also known as:
Genus:Oenothera
Family:Onagraceae (Evening Primrose)
Life cycle:biennial, short-lived perennial
Origin:native
Habitat:part shade, sun; fields, along roads, edges of woods, edges of streams
Bloom season:July - October
Plant height:2 to 6 feet
Wetland Indicator Status:GP: FACU MW: FACU NCNE: FACU
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 4-petals Cluster type: spike

[photo of flowers] Leafy spike of yellow flowers at the end of the stem, blooming from the bottom up, a few to several open at a time. Flowers are 1 to 2 inches across with 4 yellow heart-shaped petals and 8 yellow stamens surrounding a style with a cross-shaped stigma in the center. The stamens and style are typically shorter than the petals.

[photo of sepals] The 4 sepals behind the flower are ½ to 1¼ inch long and bend back away from the flower as it develops, pairs typically connected along one edge (connivent) until the flower opens, and are variously hairy, sometimes with glandular hairs. The calyx tube, connecting the ovary nestled in the leaf axil and base of the flower, is ¾ to 2 inches long and resembles a flower stalk. The flowers open in the evening and close up during the heat of the day.

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

[photo of leaves] Leaves are up to 8 inches long and 2 inches wide, lance-elliptic, tapering to a point at the tip, slightly rough to the touch, hairless or with fine white hairs, toothless or with small teeth, and little or no stalk. Leaves tend to fold up some from the prominent central vein and edges are often somewhat wavy. Color is olive to light green and there are often small leaves sprouting from the leaf axils. The stem is stout, reddish or light green, covered in white hairs, and unbranched or branching.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is a capsule ¾ to 1½ inches long, tubular but tapering some at the tip end, with 8 tiny erect lobes at the tip and variously hairy. Inside are tiny black seeds.

Notes:

A very common species, Common Evening Primrose is easily confused with the closely related Northern Evening Primrose (Oenothera parviflora). O. biennis usually has larger flowers but the sizes and other characteristics overlap in range between the two species so distinguishing them is difficult. For O. parviflora, look for a small ridge or knob at the tip end of the sepal, which O. biennis lacks, and more spreading hairs on the sepals. There are 2 varieties of O. biennis in Minnesota: var. canescens plants are more or less densely covered in appressed or curved hairs, few or none of which are glandular, var. biennis is more sparsely hairy with some gland-tipped hairs. It can grow into quite a robust plant in cultivation.

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More photos

Photos by K. Chayka taken in Ramsey and Lake counties. Photos courtesy Peter M. Dziuk taken in Anoka and Ramsey counties.

Comments

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

Posted by: Mary - Stearns co.
on: 2008-06-08 17:42:38

Thanks, you've helped me to put a name to another wildflower that I took a picture of last year by a pond in Waite Park in Stearns County.

Posted by: Karol - Savage
on: 2012-06-28 13:17:56

Every day for several years I've walked by a little pond made when a house was built on the path around Featherstone lake. This year this plant showed up. I think when they built the pond they threw wildflower seeds around it but this is the first time this little beauty has appeared.

Posted by: Lisa - Bloomington
on: 2013-07-19 20:57:54

I have a new flowering plant in the rocks(landscaping edging) along the side of the street in front of my house. I've been watching it & now that it's finally blooming I've decided it is most likely the Common Evening Primrose. 1% of me isn't sure though, because it only blooms in the early morning (pre-9 a.m.) By evening the bloom almost looks burned / dried up.

Posted by: Lisa - Bloomington, MN
on: 2014-05-10 16:08:52

I discovered this growing in the sandy soil near the curb at my home last summer(and used this wonderful website to I.D. it). I enjoyed it and let it be. But now - 9 months later - it seems to have given "birth" to dozens more which are coming up all over my yard!

Posted by: Donna - St Louis County
on: 2015-09-28 00:29:15

Along the bank of the St Louis River near Hoyt Lakes area

Posted by: Mary - Rosemount
on: 2016-07-13 18:35:43

Right outside my back door and yard. Family kept pulling it. I said let the weed go I want to see what it turns into. Wow! What a surprize. I couldn't get Moonflower to grow here, and yet this is a welcoming change at 3am to 6am. The huge moths and hummingbirds love it. I like late Autum, when I can collect the stalks for dry arrangements. Just like with Morel mushrooms ... FLICK & PICK... the life cycle is tough on these plants, 5-7 years to germinate.

Posted by: Nicole - Western Polk County
on: 2016-08-27 08:15:10

I had these plants pop-up in my flower gardens this year. I don't recall ever seeing them before. Unfortunately, I ended up pulling some. They are big and intimidating but once they flower, they're beautiful. I'm excited to have them and they add to my pollinator efforts.

Posted by: Davis - Butterfield Township
on: 2016-11-28 10:23:03

Found this in a patch with other natives in a brome/reed canary field.

Posted by: Molly M - Winona
on: 2017-08-18 19:16:45

I allowed 4 of these to grow in the garden, but pulled countless others. They are now 6 to 7 feet tall and starting to bloom. They were a magnet to Japanese beetles . More on them then any other kind of flower.

Posted by: K. Chayka
on: 2017-08-18 20:23:14

Molly, I would argue that just about any plant is a magnet for Japanese beetles :-( They are devouring the beans in our vegetable garden, among other things. The do seem to have a fondness for Oenothera species, though.

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