Harry tiptoes in with a shrub (10)
I believe the answer is:
poinsettia
'shrub' is the definition.
(poinsettia is a kind of shrub)
'harry tiptoes in with a' is the wordplay.
'harry' indicates an anagram (harry can mean to attack or spoil).
'with' is a charade indicator (letters next to each other).
'tiptoes'+'in'='tiptoesin'
'tiptoesin' anagrammed gives 'poinsetti'.
'poinsetti'+'a'='POINSETTIA'
(Other definitions for poinsettia that I've seen before include "bloom" , "Shrub often given at Christmas" , "poisonous bush" , "Plant with showy bracts, usu. red, pink or white" , "House plant, popular at Christmas -- tiniest OAP (anag)" .)