Garden plant making autumn stir (10)
I believe the answer is:
'garden plant' is the definition.
'nasturtium' can be an answer for 'plant' (nasturtium is a kind of plant). I am not sure about the 'garden' bit.
'making autumn stir' is the wordplay.
'making' indicates an anagram.
'autumnstir' is an anagram of 'NASTURTIUM'.
Can you help me to learn more?
(Other definitions for nasturtium that I've seen before include "flowering plant" , "Common trailing plant" , "ITMA's U-turn (anag) - flower" , "bloomer" , "Garden climber" .)