Flower is nothing to terribly rich daughter (6)
I believe the answer is:
orchid
'flower' is the definition.
(orchid is a kind of flower)
'nothing to terribly rich daughter' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'to terribly' is an anagram indicator.
'daughter' becomes 'd'.
'rich' is an anagram of 'rchi'.
'o'+'rchi'+'d'='ORCHID'
'is' acts as a link.
(Other definitions for orchid that I've seen before include "Common houseplant" , "Plant with showy flowers" , "Often prized flowering plant" , "Tropical flowering plant" , "Unusually shaped, beautifully coloured flower" .)