Waiter is moving plant (8)
I believe the answer is:
wisteria
'plant' is the definition.
(wisteria matches up with the definition plant)
'waiter is moving' is the wordplay.
'moving' indicates anagramming the letters (letters are moved around).
'waiter'+'is'='waiteris'
'waiteris' is an anagram of 'WISTERIA'.
(Other definitions for wisteria that I've seen before include "I saw tire in this vine with the long flower clusters" , "Climber" , "Vine with pendulous clusters of flowers" , "Climbing lilac-flowered shrub" , "A flower, I swear it" .)