Self Sufficient Hydrangea

Is it really necessary to deadhead or prune your Hydrangeas?

Hey! Let me out of here.
Hydrangea trying to push through the trunks of
a Rose of Sharon (Hibiscus syriacus)

 This old mop head 
(Hydrangea macrophylla)
has bloomed the same as usual 
without any pruning at all.
You can see the old dry heads 
if you look carefully.
It had great winter interest too.
How I love plants that 
take care of themselves!