I have read that some prefer to describe things from life, at the scene, while others like to recollect and write later, when back at home after am event.
Today I am doing the latter, recalling the choir of pink and blue forget-me-not flowers, the yellow of the dandelions, the violet-blue bugle pagodas and the white tipped sprays of bittercress. In Medlar wood there is the drooping purple green hood of a wild arum (or cuckoopint).
As Timothy Morton (2007) says "Some nature writers think that they are receiving a direct transmission from nature, when in fact they are watching a mirror of the mind."
Morton, T. (2007) Ecology without Nature. Rethinking Environmental Aesthetics. Harvard University Press, Cambridge Massachusetts and London, England