Oenothera biennis (Common Evening Primrose)
| Also known as: | |
|---|---|
| Genus: | Oenothera |
| Family: | Onagraceae (Evening Primrose) |
| Life cycle: | biennial, short-lived perennial |
| Origin: | native |
| Habitat: | part shade, sun; wet to dry soil; prairies, dunes, roadsides, railroads, waste places, woodland edges, cliffs, shores, river banks |
| 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): |  |
| National distribution (click map to enlarge): |  |
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Detailed Information
Flower: 
![[photo of flowers]](/udata/r9ndp23q/yellow/common-evening-primrose_0817_101414.jpg)
Elongating leafy spike of yellow flowers at the tip of the stem, with flowers blooming at or near the tip and fruit forming below. 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 and floral tube]](/udata/r9ndp23q/yellow/oenothera-biennis-common-evening-primrose_0725_113916.jpg)
The 4 sepals behind the flower are ½ to about 1 inch (12 to 22+ mm) long and bend back away from the flower as it develops, pairs typically connected along one edge (connivent) until the flower opens, are yellowish-green and variously hairy, sometimes with glandular hairs. The floral tube, connecting the ovary nestled in the leaf axil and base of the flower, is ¾ to 1½ inches (20 to 40 mm) long and resembles a flower stalk. The flowers open in the evening and close up during the heat of the day.
Leaves and stem:
![[photo of leaves]](/udata/r9ndp23q/yellow/oenothera-biennis-common-evening-primrose-0727_162009.jpg)
Leaves are basal and alternate, the basal and lower stem leaves 4 to 12 inches (10 to 30 cm) long and ¾ to 2 inches (2 to 5 cm) wide, pointed at the tip, tapering at the base, slightly rough to the touch, mostly hairless, and stalked, becoming smaller and stalkless or nearly so as they ascend the stem. Edges are mostly flat, sometimes a bit wavy, and minutely toothed, the teeth often widely spaced. Color is olive to light green and there may be small leaves clustered in the leaf axils. Stems are mostly erect, branched or not, stout, reddish or light green, variously covered in stiff spreading to appressed hairs that may have a pimple-like base (pustulate).
Fruit:
![[photo of developing fruit]](/udata/r9ndp23q/yellow/oenothera-biennis-common-evening-primrose-0727_161958.jpg)
Fruit is an erect to ascending capsule ¾ to 1½ inches (20 to 40 mm) long, tubular but tapering some at the tip end, with 8 tiny erect lobes at the tip and variously hairy across the surface. Inside are angular seeds about 1 mm long.
Notes:
A very common species, Common Evening Primrose is easily confused with the closely related Northern Evening Primrose (Oenothera parviflora) and Hairy Evening Primrose (Oenothera villosa, formerly O. biennis var. canescens). O. biennis usually has somewhat larger flowers but the sizes and other characteristics overlap between the three species so distinguishing them can be difficult, especially when fresh sepals are not present. For O. parviflora, look for a small ridge or knob at the tip end of the sepal, which O. biennis and O. villosa lack. O. villosa sepals can be striped or tinged red (but not always) where O. biennis sepals are green to yellowish-green.
The types and density of hairs on all 3 species are rather variable: stiff appressed hairs, longer spreading to ascending hairs with or without a pimple-like base, and with or without glandular hairs. Flora of North America notes that when flowers fade, O. villosa petals turn orange where O. biennis turn more whitish and somewhat translucent, but we aren't yet convinced orange is limited to O. villosa. Leaves of O. biennis are also said to be more flat along the edges where O. villosa tend to be more wavy. Two subspecies of O. villosa with different characteristics make the distinctions even more challenging. In the coming seasons we will be seeking out good field specimens and working out better or more consistent distinctions, as well as clues on how any of these characteristics may change during the course of the season.
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More photos
branching Common Evening Primrose plant
first year rosette
winter seed head
garden grown Common Evening Primrose
branching Common Evening Primrose plant
first year rosette
winter seed head
garden grown Common Evening PrimrosePhotos by K. Chayka taken in Lake and Ramsey counties. Photos by Peter M. Dziuk taken in Anoka and Ramsey counties.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?
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.
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.
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.
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!
on: 2015-09-28 00:29:15
Along the bank of the St Louis River near Hoyt Lakes area
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.
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.
on: 2016-11-28 10:23:03
Found this in a patch with other natives in a brome/reed canary field.
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.
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.
on: 2019-08-03 08:36:53
This website is so much better than ALL the identification I have in my collection. Thank you for making this information available, I had no idea there were so many species of Oenothere in Minnesota.
on: 2020-10-17 14:00:35
Saw this sweetie growing near a small pond off the path west of Medicine Lake.
on: 2021-04-19 10:50:50
Hi I believe I had a evening primrose in my garden next to my sliding glass doors and it got as as tall as well. I cut it back in the fall. It doesn't look like it's coming back but it attracted hummingbirds and I really loved it! Just wondering if it will comeback or if I can buy the plants or seeds somewhere near me? Thank you for any help! Lisa
on: 2021-04-19 15:08:05
Lisa, this evening primrose is biennial so if it bloomed last year the same plant will not return, but if any seed was formed before you cut it back it may have reseeded itself nearby. We do not track who sells what so check the native plant vendors, some of which may carry this species.
on: 2022-07-01 09:22:15
was yanking these tall "weeds" out of my flower beds when i took a picture for identification & discovered what it was. love that this "weed" is described as low-maintenance & virtually pest-free! thinking of all the perennials i've purchased & fussed over for the last umpteen years, and this thing pops up. grrrr.
on: 2022-07-09 21:59:56
There's a couple growing up out of the gravel in my driveway.
on: 2022-08-17 02:38:38
This showed up growing among the rocks on our beach. There's only one plant, and it amazes me that any flower can grow in an area quite windy, only watered by rain, about 7 hours of bright sun, in sand, and in the shade of an oak tree.