You're right. Euphorbia lathyris.
Is there a photo?
I haven't grown them. I didn't think they were hardy
Go out and squeeze it and see if you get a very pungent, musty sort of smell. I think that's Solanum ducamara, Bittersweet, woody nightshade.
Note the resemblence of the flowers to spuds, same family.
You won't need to buy seed Passionate, save the ones this plant produces. You might get some variation but they'll be much the same
One of the nightshades, I always forget which is which. The one known as Woody Nightshade I think
They're not ripe yet but yes
Agree Chrissy, I missed that in the OP. Nothing grows naturally like that Roops. Nor stay that way without frequent snips
I can't see the leaves clearly but my first thought was godetia, now called clarkia, (or maybe it's clarkia that's now called godetia)