Southern Finland. I've found these and some more bluish ones. They are fairly small (the flower itself is about 4-6cm) and have these long, pretty thick leaves. It isn't visible in the photos, but the petals have this glittery look on them.
Here's one of the blue ones, in a vase:
I've mostly seen them near yards or gardens, so I think they aren't native.
This plant should not be thriving in this environment. It is growing on compacted oxisol in an area that gets over 4 metres of rain. Yet here it is, growing completely out of control. Nothing makes sense. Climate change?