Don't trim it at all. Mine look the same as yours due to the bad winter here in NE Ohio. I'm taking a wait and see approach and plants are running 2-3 weeks behind here. These beauties usually rebound, but my first poor experience with my Nikko Blue was overtrimming (ie. long stems) for a friend's wedding and then having to wait 2 years for it to bloom again. Be patient, I'm betting it may be 2 years due to this winter. The most I've ever trimmed mine since is removing the dead mops in the spring (perhaps 4", just a bit above the bud). Hydrangeas love to be fed acid-loving fertilizer and tons of water. To go blue, I give my Nikkos lots of cold leftover coffee and grounds. Take a look at these articles: http://homeguides.sfgate.com/hydrangea-pruning-hard-frost-72951.html

http://homeguides.sfgate.com/prune-hydrangeas-dead-wood-stems-46868.html

http://www.hydrangeashydrangeas.com/hydrangea_would_not_bloom.html

There's another post with regard to low foliage on old wood hydrangeas. They are saying wood is dead, plant is starting over, could well be. I'm still waiting until at least 1st week of June, then may trim down.

What was the lowest winter low in your are? -20? If so, not a chance those stems survived. You can wait to see what they do but they're likely dried and beginning to rot. Bend and/or twist a few and they'll likely snap somewhere with *very little* effort. There have been no inconsistencies this past winter -everyone got whacked.

I wish the forum had sticky threads because these questions are getting repetitive.

Hydrangeas will bud out along the length of the stem if not killed back by winter cold, not just at the base. By this time of year you should be seeing good strong leaf growth all along the stems and even the hint of flower buds provided the plant was not set back by winter cold.

Those bare stems are dead.

Just to repeat Springwood Gardens' opinion :-))