Mother and doctor of many years bloom (8)
I believe the answer is:
marigold
'years bloom' is the definition.
The definition and answer can be both plants as well as being singular nouns.
Maybe there's a link between them I don't understand?
'mother and doctor of many' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'and' is a charade indicator (letters next to each other).
'doctor of' becomes 'rigol' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'many' becomes 'D' (Roman numeral for l00).
'ma'+'rigol'+'d'='MARIGOLD'
Can you help me to learn more?
(Other definitions for marigold that I've seen before include "Bright orange-yellow garden flower" , "Flower - grim load (anag)" , "Yellow or orange flower" , "Orange daisy" , "Orange-flowered plant" .)