Tells one the way to train the rose round it (6)
I believe the answer is:
orders
'tells' is the definition.
('order' can be a synonym of 'tell')
'train the rose round it' is the wordplay.
'train' is an anagram indicator (to train can mean to grow something into a shape).
'round' is an insertion indicator.
'it' becomes 'rd' (I can't explain this - if you can you should give a lot more credence to this answer).
'rose' anagrammed gives 'oers'.
'oers' enclosing 'rd' is 'ORDERS'.
'one the way to' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for orders that I've seen before include "Holy - -" , "Instructions given as to waiters" , "Dictates, commands" , "Commands and edicts" , "Commands these priests and nuns?" .)