Caught this yesterday in my sister's garden, a cottage garden par exellence. Love plant and this doesn't show the full colour which is a deep and vivid blue.
This is the hardy variety although my snap doesn't do it justice.
I fell in love with the delicate pale blue flower of the plumbago when living in Greece. I knew of only one the same growing outdoors in the UK. That plant a friend had growing in a tub in her long porch, which caught lots of sunshine. It grew across one wall and down the front of the porch, huge and quite beautiful. Alas my porch isn't sunny enough so I will grow the hardy varierty as I love that blue anyway.