Since that are North American prairie bulbs I think they should be hardy enough to survive in Scotland. We are pretty cold here same isotherm as Newport in Shropshire which recorded the lowest temp in England not so long ago. The bulbs just need well drained soil. They have become a bit of a nuisance here, spreading like mad and the leaves are a bit ugly when the flowers have finished.
I tried them last year at the bottom of a slope in the school garden I look after - I thought they liked moisture retentive soil? I wasn't impressed with the flowers though, but yours are beautiful.
My blue ones are in flower now here in Cornwall, I also have some very pale lemon/cream flowered ones which flower about a month later. They are definitely are loved by slugs and snails.
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"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
A A Milne