Part of flower outside wilts when denied one form of support (8)
I believe the answer is:
pedestal
'form of support' is the definition.
(I know that pedestal is a type of support)
'part of flower outside wilts when' is the wordplay.
'part of flower' becomes 'petal ' (I've seen this before).
'outside' is an insertion indicator.
'wilts when' becomes 'des' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'petal' going around 'des' is 'PEDESTAL'.
'denied one' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for pedestal that I've seen before include "Desk drawer unit" , "Column support, on which one is worshipped" , "Those worshipped are put on one" , "Plinth, base" , "A statue stands on it" .)