Sakgit Gardens had a stunning array of euphorbia. This 'Tasmanian Tiger' isn't hardy for me, but if you are in zone 7 or warmer, keep an eye out for it.
This Euphorbia 'Ascot Rainbow' is only listed as zone 6, but the representative from Skagit said they had preliminary trials showing it might be actually zone 5. Not as amazing as some of their others, but still, I think it is headed for my garden this year. This is the flowers -- leaves are green edged in yellow.
This is a 2-for-1 picture: On the left, a Uncinia. Lovely, but only hardy to zone 7. On the right, Oenothera 'Shimmer' (zone 5, If I recall correctly.) I LOVE the oenothera foliage. It will get large yellow flowers eventually, but with leaves like that, who needs them?
Yes, we're talking about perennials, and yes, those are gerbera daisies. This is a new series from Northern Innovators which they say is hardy to at least zone 7. I was all excited about the perennial, until I saw the zone... but, their representative said it should be hardy to at LEAST zone 7. They haven't tested in colder zones yet, so we'll see. I don't know if they'll make it all the way to my zone 5, but if you are in zone 6, I'd give them a try. The flowers are smaller than regular gerbs, but still very nice, and they'd make amazing cut flowers.