I should point out that I always loathed being forced to 'interpret' stuff in English at school.
"And what do you think the author meant by that?" I would be asked.
"How the f** should I know". is in my head.
"maybe he couldn't think of anything else to put" I would actually say, obtaining scorn and zero enlightenment from my teacher.
I find interpretation by known symbology interesting - I've seen very interesting things about what people put in paintings.
But poetry is far too obscure for me - "the blue-bird sings" means a bird, which is blue, is singing. If they want to say something else they should bloomin' well say it!.
**epiphany**
I've just realised - I am far more comfortable with visual symbology (I devour maps at every opportunity and they are almost totally symbolic) than I am with words. I always want to take words literally and it annoys me when word sare used to obscure things rather than expose them.
At this realisation I will step away from any discussion of poetical interpretation as I am wholly unqualified for it.