Some extreme care needed to return arrangement of flowers (6)
I believe the answer is:
raceme
'arrangement of flowers' is the definition.
(a raceme is a cluster of flowers)
'some extreme care needed to return' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'to return' says the letters should be written in reverse.
'emecar' is hidden in the letters of 'extreme care needed'.
'emecar' written backwards gives 'RACEME'.
(Other definitions for raceme that I've seen before include "Flower cluster (botany)" , "Long cluster of flowers along the main stem" , "flower arrangement" , "Care about me with flowers spaced along a central stem" , "Long cluster of flowers on one stem" .)