Meadow flower's opening — a bit of foliage (4)
I believe the answer is:
leaf
'a bit of foliage' is the definition.
(I've seen this before)
'meadow flower's opening' is the wordplay.
'meadow' becomes 'lea' (I've seen this before).
'opening' suggests taking the first letters.
The initial letter of 'flower' is 'f'.
'lea'+'f'='LEAF'
(Other definitions for leaf that I've seen before include "Turn over a new one to reform" , "needed for making a longer table" , "Page; piece of tree" , "In fall, one dislocated" , "Sheet of written material" .)