Can someone please tell me if this is an annual or perennial?

I planted it in a tall urn to trail over the side. When first planted, it had pretty purple flowers. Now I just have long vines without flowers. Does this mean they aren't getting enough sun? Does it just bloom in the spring? Do I need to prune them back a bit? I have it planted in 2 urns with Sarcacocca. One on the northwest side of the house and the other is planted on the northeast side of the house.

I'm in zone 8b, British Columbia.

Thank you for your help.