I have deliberately not dead-headed the plant, because I have read that the old blooms help to protect the new shoots during the Winter. I'll cut them off in the Spring.
You can see why this type of Hydrangea is sometimes called the "Mop-head Hydrangea", can't you?
Actually, I think the old faded blooms have a certain stark beauty of their own:
New shoots are appearing in the crown of the plant as well as on the existing branches, so I'm hopeful that the plant will fill out a bit next year and become more bushy.
You'll notice that I have left some fallen leaves in the pot, rather than clearing them away, because I think this may also protect the plant's roots.