I have a garden on the front corner of my property that has a strong southeast exposure. What I find interesting is that this garden seems to defy the rules. It gets strong morning sun and by 2:00 is in full shade. Hardly a sunny spot. Everything I have in the garden requires full sun exposure, and blooms beautifully. I think the warm SE exposure has a lot to do with this. It seems to make up for the hours the plants spend in the shade.
The other thing the plants in this garden do is bloom early. I consistently get blooms 3-4 weeks earlier than expected. Again I think this is the SE exposure. This coreopsis (tickseed) is a great example. It's firing off flowers now. It isn't supposed to let go unitl June!