A foolish sheep rejected plant (9)
I believe the answer is:
amaryllis
'plant' is the definition.
The answer is an example.
'a foolish sheep rejected' is the wordplay.
'foolish' becomes 'silly' (similar in meaning).
'sheep' becomes 'ram' (male sheep).
'rejected' shows that the letters should be reversed in order.
'silly'+'ram'='sillyram'
'sillyram' back-to-front is 'maryllis'.
'a'+'maryllis'='AMARYLLIS'
(Other definitions for amaryllis that I've seen before include "belladonna lily brought this about" , "Trumpet-flowered bulb" , "Bulb with showy flowers" , "Plant with showy flowers - I rally Sam (anag)" , "Bulbous plant with trumpet-shaped flowers" .)