Self-seeded, but I don't remember from which species. Flowers are white, open in evening, fade to pink. No yellow center to flowers. Mid-green leaves.

http://www.fireflyforest.com/f...


I can't see the entire rosette awarded, It may even be Oenothera speciosa 'Rosea', It is a shady spot, is it true?

my Oenothera speciosa 'Siskiyou'

maybe
Oenothera acaulis
http://www.robsplants.com/plan...

Don't think I agree....Still researching...

Not a shady spot - the color balance on the photo comes from having to take the photo when the flowers opened, after dusk had arrived. The leaves aren't right, I believe, for berlandieri, acaulis, or cespitosa. Oenothera speciosa (at least the ones I grow) are more generous with their hours of flowering.

I think it is Common Evening Primrose, Oenothera biennis
http://www.wildflower.org/gall...

frostweed said:I think it is Common Evening Primrose, Oenothera biennis
http://www.wildflower.org/gall...

my A. biennis

do you think they are similar?

The plants on Bamira's picture are old and overgrown, so no those don't look similar, but on a young plant, they do look similar.

Definitely not Oenothera biennis. Those grow in my garden (as an occasionally tolerated weed), and are strong upright growers with yellow flowers. My mystery plants are whispy (no strong upright stalk) with pure white flowers. I realize that my photo doesn't show the habit of the plants all that well (there's that dusk again), but these plants are no more than 6 inches tall, with no inclination to get any taller.

Yep, not O. biennis. That stuff towers over my head!

Take a look at this one, Oenothera caespitosa.
Common names: Dwarf Evening primrose, White Tufted Evening primrose, Morning-lily, Handkerchief Plant.
http://www.nps.gov/arch/learn/...

Well it looks like I was way off the mark and caespitosa looks more like it.

Caespitosa is indeed much closer, but still not it. Caespitosa's petals are distinctly cleft, while mine are indistinctly fringed or entire-margined. Caespitosa's leaves look to be gray-green and sturdy, forming a robust clump, while mine are mid-green and floppy, forming a much looser plant. In fact, I'd like to grow caespitosa sometime

Perhaps it might help if you could add more images, details of the foliage, petals, etc. Something for size reference?

Once the identification is made, I want to be on a list to beg for seeds.

Could be White Evening Primrose (Oenothera pallida), but I can't really see enough of it to be sure.

There are many species of white-flowered Oenotheras growing in the American West, but most of them are difficult to grow outside their native range. I've tried growing Tufted Evening Primrose (Oenothera cespitosa), for example, which is native to my state (although at the other end), but have never been able to keep them alive for very long. We'll get a stretch of hot humid weather in the summer and that's the end of them. They are so well adapted at preventing moisture loss through their leaves that, when confronted with high humidity, they just melt.

Oenothera pallida is one of the exceptions and can occasionally be seen in gardens in the East.

Yes, I agree we need more photos :-)
This one isn't the greatest, but it gives a better impression of overall size (note the lawn grass next to it) as well as color and habit of the leaves. The photo is not of a single plant, but a cluster of self-sown plants. It was taken around 7pm, and the flowers haven't opened up yet.
I'm growing O. pallida as well this year, and its leaves are quite different in appearance. No blooms on that one, probably not before next year.

My O. pallida has now bloomed, and has quite different buds (puffy, hairy) from the ones on my mystery plants:



These are more similar to the twisty kind seen on O. glazioviana (another species that grows much taller).