How's about an update to get us into June?
Close-up of flowers on Rheum rhizostachyum:
Buds on Silene bolanthoides:
Rhodiola rosea:
Another Rhodiola... labelled as Rhodiola roseum purpureum when I bought it locally, but I'm not sure absolutely sure if that is correct; it has remained very small and has been going dormant after blooming, which seems odd:
Phlox hendersonii:
Aquilegia laramiensis:
This is not quite the floral extravagance that I hope for in the future, but I guess it's okay for a second-year seedling - Erigeron nanus, bless it's little heart : :) 
Linum cariense:
Euphorbia capitulata, as the flowers go from yellow to orange: