Rootstock in poor rising (5)
I believe the answer is:
orris
'rootstock' is the definition.
(preparation of iris rootstock)
'in poor rising' is the wordplay.
'in' says the answer is hidden in the clue.
'ORRIS' is hidden within 'poor rising'.
(Other definitions for orris that I've seen before include "Fragrant rootstock" , "Flag" , "perfumery ingredient" , "Type of flower" , "Iris with fragrant rhizome" .)