Did well if shoulder knitted (10)

I believe the answer is:

flourished

I'm a little stuck... Click here to teach me more about this clue!

'did well' is the definition.
(I've seen this before)

'if shoulder knitted' is the wordplay.
'if shoulder' anagrams to 'FLOURISHED'.
However, I am not clear how this is indicated.

Can you help me to learn more?

(Other definitions for flourished that I've seen before include "Showed off" , "Brandished" , "Was blooming" , "Did well" , "grew and blossomed" .)

I've seen this clue in the Sydney Morning Herald.

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