Returning Columbine

For many years I tried to get columbine to return after winters in my Laguna garden, but it never did and I always had to replant it every year. I remember reading about how some gardeners even consider it a problem because it reseeded so readily. Those were problems I wanted! Here in my SJC garden I have finally accomplished my goal and this is the fourth year it has returned in abundance. What is the difference? It may be the type of columbine I planted. This one is a simple, more native type that I found at a small nursery while the other ones I used were the fancy hybrids that are two toned (although I do have some of those that return every year here too). But most likely it is a subtle change in climate. Being on a north facing hillside, the Laguna garden stays pretty shady and cool until summer. Although only a few miles away, there is definitely more spring warmth and sunshine in SJC's gardens. It may simply be a matter of finding the exact spot preferred by this dainty flower.