Note former cane plant with yellow flowers (9)
I believe the answer is:
goldenrod
'plant with yellow flowers' is the definition.
'note former cane' is the wordplay.
'note' becomes 'g' (musical note).
'former' becomes 'olden' (I've seen this before).
'cane' becomes 'rod' (I've seen this before).
'g'+'olden'+'rod'='GOLDENROD'
(Other definitions for goldenrod that I've seen before include "Autumnal plant" , "Yellow-headed garden plant" , "Plant with spikes of tiny golden flowers" , "Yellow-flowered plant" , "bloomer" .)