Platform that's small for flowers (7)
I believe the answer is:
daisies
'flowers' is the definition.
(daisy is a kind of flower)
'platform that's small' is the wordplay.
'platform' becomes 'dais' (dais is a kind of platform).
'that's' becomes 'ie'.
'small' becomes 's' (abbreviation - e.g. clothes size).
'dais'+'ie'+'s'='DAISIES'
'for' acts as a link.
(Other definitions for daisies that I've seen before include "Flowers pushed up by the dead?" , "Flowers with yellow centres" , "Asides I use to describe flowers" , "Asides I address to the flowers" , "Lawn flowers" .)