A pest crawling round the little flower (5,3)
I believe the answer is:
sweet pea
'flower' is the definition.
(I've seen this before)
'a pest crawling round the little' is the wordplay.
'crawling' indicates anagramming the letters (letters crawl around).
'round' means one lot of letters goes inside another.
'the little' becomes 'wee' (I've seen this before).
'a'+'pest'='apest'
'apest' anagrammed gives 'stpea'.
'stpea' enclosing 'wee' is 'SWEET PEA'.
(Other definitions for sweet pea that I've seen before include "Fragrant climber" , "Saccaharine legume for favourite flower" , "Climbing pant" , "Climbing plant with pastel-coloured flowers" , "Peseta we paid for climbing garden flower" .)