Clearly not dead, there is new growth coming up from the bottom. ;)

You may have had winter kill of previous years growth though. I can see some buds on those bare stems, are they swelling at all, or brown, hard and dry. You could use your fingernail to scratch the bark on an outer stem of your hydrangea, reveal the wood inside. If you see any green there is still life there and you should be patient a while longer. If all is brown, no green or light color to indicate life, make a scratch lower on the stem. If you still can't find anything alive, you can cut those bare stems off at the base.

Lots of areas had harder than usual winters the last couple of years. Depending on how early and how late your worst low temperatures occurred, you could have lost growth you might not have with a more typical winter.

I agree. This year, I have one mophead in the north of the house with -count this- only one bloom and, on the other side of the walkway, another with no blooms. An nearby oakleaf hydrangea also has no blooms either. Yet, further away or in the south (& more protected side) of the property, other mopheads, lacecaps and oakleafs are already blooming or in the broccoli phase.

I noticed that this winter we again had lots of temperature fluctuations. These probably confused the shrubs and instead of staying dormant, they may have started some growth that got zapped when the temps went down. This probably killed flower buds on the north side of the house and allowed the ones in the south to bloom fine. You may have had similar issues and got shrubs with sticks and all growth coming from the plant. That is how my no bloom mopheads looked like in March.

The mophead in the north with exactly one bloom looked like dead sticks, the blooming stem leafed out thru the middle and then leafed out higher up. You can never learn what they will do so I wait until May to prune off the dead sticks so they have a chance. But many times, they do not make it or they only leaf out part ways (too much winter damage apparently). If in the northernmost states, wait until mid to late May. Or cut in 1/2" to 1" increments until you hit green (but this method may result in cutting off flower buds) so be aware. More winter protection (any winter protection in my case) may prevent this in future years.