Weird - I posted a reply a few days ago, but now it has disappeared...

Try again...
Yes, it dies down in winter.
New leaves are likely to show in March (in the UK), though elsewhere that is likely to vary.
Position: to generalise: light shade.
It will grow in a variety of media, but I would try it in mossy/peaty compost.
More info, including piccies, in this article I wrote some while ago - see link.

Mike

Viola selkirkii is a strange violet..I have it but I can't say that I grow it!! It disappear in winter...Later, new seedlings appear here and there when I think it is lost. It seems that this year it grew better when I changed it for a more light place.It do quite well in peat potting soil.
I also noticed that strong frost helps the bloom.
Good luck with it