Part of spring vegetable uprooted (3)
I believe the answer is:
may
'part of spring' is the definition.
(May is a spring month)
'vegetable uprooted' is the wordplay.
'vegetable' becomes 'yam' (yam is a kind of vegetable).
'uprooted' shows that the letters should be reversed in order (in a down clue, letters go up).
'yam' back-to-front is 'MAY'.
(Other definitions for may that I've seen before include "Hawthorm blossom" , "plant that's tropical making comeback" , "Spring" , "Time" , "Month; hawthorn" .)