Tracing a Memory

Flower images recur over and over in my image making and I often wonder where the memories that drive the interest come from. 
Drawing from life has always seemed to attract me and you would think there would be an easy understanding of the creative links. 
I do know that gardens in general and flowers in particular offer something not easily found in other places and things. I also know that essays have been written and degrees offered all around the study of gardens in their physical and metaphysical states and then of course there are biblical stories of gardens and the creations within. 
I just wonder why I would choose to sit in place and make a drawing that records a moment in time, captures, the event or feeling and makes a record to come back to.
Is it the colour or the shape? 
Is it the air?