Stalk underground art whizz discovered by women's centre (7)
I believe the answer is:
rhizome
'stalk underground' is the definition.
(type of stem that grows underground)
'art whizz discovered by women's centre' is the wordplay.
'art' becomes 'r' (I can't justify this - if you can you should believe this answer much more).
'discovered' says to take the centre.
'by' says to put letters next to each other.
'centre' says to take the centre.
The middle of 'whizz' is 'hiz'.
The middle letters of 'women' are 'ome'.
'r'+'hiz'+'ome'='RHIZOME'
(Other definitions for rhizome that I've seen before include "Underground rootstock of a plan" , "Underground plant stem producing roots and shoots - zero him (anag)" , "that supplies stock" , "Subterranean plant stem" , "part of plant" .)