First, the species is hydrangea macrophylla (big leaf). There are hundreds if not thousands of cultivars, though. I'm gonna go out on a limb and say it's a white blooming variety, because of lack of coloration the leaves. And yours would appear to bloom on old wood only (buds are set this year for next year, but have been killed in years past due to harsh winters - macrophylla don't like temps below 0 to -10).

There's no real way to find out what cultivar it is until it blooms, though. To protect buds, you can try piling leaves over the plant in fall and maybe even throwing pine bows, landscape fabric, or an empty 7-gallon pot over it in December and remove in early May.

The other possibility is that you pruned it and cut off the buds. If so, leave it alone this year, hope for a milder winter, and don't cut off the bare sticks in spring until June, when you'll know whether they survived the winter.

In my Zone 6, there is usually only a 50-50% chance that a machrophyll hydrangea will bloom. The winters are too often too cold and too much freezing and thawing and freezing going on in the spring. If you are in Zone 6, you might try planting that hydrangea in the most protected corner you can find--where the cold winter winds won't hit it and where it will get some warmth, like at the foundation. A corner of the house that protects it on two sides would be helpful--as long as it isn't on the north side.

Myself, I've switched to Annabelles and paniculata hydrangea. They are more reliable bloomers than macrophyll's are. I do have a few of the newer compact macrophyll's (at least I think they are) that bloom on both old and new wood. That way, if the winter kills the first spring bloom (which would be on old wood), the plant can still bloom later in the summer on the new wood it produces.

Fortunately, whatever kind of hydrangea you get, they are all beautiful!

Kate