I thought it reminded me of the Morning Glory, but the flowers are smaller. I think the suggestion that it is Convolvulus arvensis has merit - from what I've found quickly, though, I am wondering if my lovely "find" has an evil down-side? Should I NOT be encouraging this? It is not very wide spread (yet), but is much prettier than the ice plant and ivy it has popped up among. From what I've read, I am wondering if I am dancing with the devil?

Strophostyles umbellata?

MaryMebo - that is the trouble with common names. Different plants get given the same common name and there is no standardisation. Maybe the 'Bleeding Heart' you are thinking of is Lamprocapnos spectabilis formerly Dicentra spectabilis. And no, the two plants are not related.

Begonia?