Petals can be of such colours (6)
I believe the answer is:
pastel
'such colours' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'petals can be' is the wordplay.
'can be' indicates anagramming the letters.
'petals' is an anagram of 'PASTEL'.
'of' is the link.
Can you help me to learn more?
(Other definitions for pastel that I've seen before include "Of a colour, subtle" , "Crayon - gentle shade of colour" , "A light delicate shade of colour" , "Delicate and pale in colour" , "Chalky crayon" .)