Very green, dewy ground around island and river (4-4)
I believe the answer is:
wide-eyed
'very green' is the definition.
(both can mean naive or innocent)
'dewy ground around island and river' is the wordplay.
'ground' indicates an anagram ('grind' the letters into a new form).
'around' indicates putting letters inside.
'island' becomes 'i'.
'and' means one lot of letters go next to another.
'river' becomes 'dee' (River Dee).
'dewy' is an anagram of 'wyed'.
'i'+'dee'='idee'
'wyed' going around 'idee' is 'WIDE-EYED'.
(Other definitions for wide-eyed that I've seen before include "Inexperienced; showing amazement" , "Showing great surprise" , "Innocent - believing" .)