Shrub of note with instant appeal (6)
I believe the answer is:
mimosa
'shrub' is the definition.
(mimosa is a kind of shrub)
'note with instant appeal' is the wordplay.
'note' becomes 'mi' (as in 'do re mi').
'with' says to put letters next to each other.
'instant' becomes 'mo'.
'appeal' becomes 'SA' (old-fashioned abbreviation for sex appeal).
'mi'+'mo'+'sa'='MIMOSA'
'of' acts as a link.
(Other definitions for mimosa that I've seen before include "Sensitive plant genus; so maim (anag.)" , "So maim with tropical shrub bearing fragrant flowers" , "One growing sensitive" , "cocktail" , "Australian 15 across" .)