I have a couple hydrangeas in my own garden. They both are budding up quite nicely in sync with everything else. Give it another week or so if you had a cold spell. You should definitely see some sign of growth. They need moist soil & dappled light.

What kind of Hydrangeas? Our macropetala types are actually evergreen(ish), but the paniculata types are mostly still dormant.
Try the scratch test. Scratch a tiny section of bark in a stem. If it is green underneath then the plant is still alive.

Where you live, it might be a bit early for any signs of growth, but here in the south, our hydrangea macrophyla, the mophead type, are already in full leaf. Have they dried out at the root?

If it reassures you Namtar, mine are only just coming to life this year! They can be very thirsty plants but don't keep in over watered soil.

Thanks for all the feed back. Have been waiting for them to sprout but no joy. There is a little green towards the base but the rest of the plants appear to be dead. Will try again this year if any garden centers open.