Ring up to import island flower (5)
I believe the answer is:
lilac
'flower' is the definition.
(I've seen this before)
'ring up to import island' is the wordplay.
'ring' becomes 'call' (call on the phone).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'to import' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'call' reversed gives 'llac'.
'llac' enclosing 'i' is 'LILAC'.
(Other definitions for lilac that I've seen before include "Shade" , "Pale violet hue" , "Light-purple" , "Shrub with fragrant pink, purple or white flowers" , "Drop by about one, turning" .)