It grows careless at the welfare centre (4)
I believe the answer is:
flax
'it grows' is the definition.
The definition suggests a singular noun which matches the answer.
'careless at the welfare centre' is the wordplay.
'careless' becomes 'lax' (synonyms).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'centre' indicates the central letters.
The middle of 'welfare' is 'f'.
'lax' put after 'f' is 'FLAX'.
Can you help me to learn more?
(Other definitions for flax that I've seen before include "Plant from which linen is made" , "Blue flowering plant cultivated for its seeds and fibre" , "Source of linseed" , "Linen fibres" , "Linen thread" .)