Tended to turn red with sun (6)
I believe the answer is:
nursed
'tended' is the definition.
(I've seen this before)
'turn red with sun' is the wordplay.
'turn' indicates anagramming the letters.
'with' is a charade indicator (letters next to each other).
'red' put after 'sun' is 'sunred'.
'sunred' is an anagram of 'NURSED'.
'to' is the link.
(Other definitions for nursed that I've seen before include "Tended to the sick, cared for" , "given medical attention" , "Tended to while ill" , "Cared for the ill" , "Took care of the sick" .)