In "since feeling is first," a love poem, e.e. cummings uses the metaphor of punctuation to describe his feelings.  At the very end of the poem, he states, "for life's not a paragraph/and death I think is no parentheses."  These metaphors lend themselves to many in-depth interpretations.  For life is not a paragraph, that could mean that life is not a short summary of things; a paragraph is too concise and tiny to hold all that life has.  A paragraph is limited; it can only relate so much information.  Life is not like that--it is entirely, overwhelmingly full.  As he states above, even "your eyelids' flutter" has so much beauty in it that he could go on and on about it for quite some time.  Add that to all else that life offers, and indeed, a paragraph does not suffice.  Paragraphs also follow an order, a specific format, and life is not that predictable.

Life, in this poem, can be replaced with love--cummings uses them interchangably as far as meaning goes.  So, everything that I stated above about life, can also be applied to love.  That is the metaphor for love in this poem.  If you look at who he is talking to, (he addresses "lady" in the poem) and how he focuses on kisses, and her eyelids, you can conclude that the life he is referring to is the love he feels for her.  To clarify--the metaphor for life and love in this poem is that love is not a parentheses.  Another possible metaphor for love is Spring (he says that when Spring is in the world, all else is wonderful.)  Comparing it to flowers is an off-shoot of that spring metaphor. I hope that helped; good luck!