Ring up about island flower (5)
I believe the answer is:
lilac
'island flower' is the definition.
'lilac' can be an answer for 'flower' (I've seen this before). I am not sure about the 'island' bit.
'ring up about' is the wordplay.
'ring up' becomes 'lila' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' becomes 'c' (abbreviation for 'circa').
'lila'+'c'='LILAC'
Can you help me to learn more?
(Other definitions for lilac that I've seen before include "Shrub with fragrant pink, purple or white flowers" , "Genus Syringa shrub" , "Light purple - flowering tree" , "Shrub with fragrant purplish or white flowers" , "Tree with purple or white flowers" .)