Poor drainage for showy plant (8)
I believe the answer is:
gardenia
'showy plant' is the definition.
The definition and answer can be both plants as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'poor drainage' is the wordplay.
'poor' indicates an anagram.
'drainage' with letters rearranged gives 'GARDENIA'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for gardenia that I've seen before include "Shrub such as the Cape jasmine" , "Shrub with fragrant flowers - in Grade A (anag)" , "Fragrant tree or shrub" , "Bad drainage can produce a fragrant flower" , "Drainage (anag) -- plant" .)