Sprang up, seeing if an absent wife rang back (4)

I believe the answer is:

grew

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'sprang up seeing if an absent' is the definition.
I can't judge whether this defines the answer.

'wife rang back' is the wordplay.
'wife' becomes 'w'.
'rang' becomes 'erg' (I can't justify this - if you can you should give a lot more credence to this answer).
'back' is a reversal indicator.
'w'+'erg'='werg'
'werg' backwards is 'GREW'.

Can you help me to learn more?

(Other definitions for grew that I've seen before include "Expanded - flourished" , "Cultivated'" , "Multiplied" , "Rose" , "Increased in size" .)

I've seen this clue in The Telegraph.

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