Hydrangeas that do not bloom reliably may do so because they are planted out of zone and need winter protection. The dried out stems in your plant photos indicate that last year's stems dried out during winter because the plant was not hardy enough. Dried out stems can be pruned if they do not leaf out by mid to late June so feel free to do that now.
When the stems dry out, the roots do not necessarily die and in this case you get a plant that leafs out by producing new stems from the base or crown. That is not a problem with hydrangeas that re-bloom (like the Endless Summer and Forever & Ever Series). But if the plant does not re-bloom, you basically end up with a plant that returns every year from the ground, has nice green leaves and produces no or few blooms.
Since hydrangea flower buds reside at the end of the stems, when the stems die, there go the flowers. In "warm" winters, the stems may survive or some stems may survive thus allowing you to see some bloomage but, if you want to get blooms [u]reliably[/u], you need to winter protect the stems just as the plant goes dormant in the Fall.
There are several techniques used to accomplish this and the most common one involves putting chicken wire around the existing bush, say 3-6 inches away from the tips of the stems. Measure the width and height. If the shrub is 2' tall and 3' wide, get chicken wire that is 3-6" taller and wider than the hydrangea. The more distance between the end of the stems and the chicken wire, the more protection the plant stems get. And if the stems are happy and warm, the flower buds will be too.
Fill the empty space with leaves from the garden. Pack them in tight. Unused leaves can be kept in a trash bag. Use these unused leaves in mid winter if/when settling occurs. You can obtain the leaves from your garden or ask you neighbors to give you theirs. I have heard of some people also using mulch and hay. Some people add a piece of cardboard on top of the chicken wire (not on top of the leaves). This helps prevent loosing leaves on windy days and allows you to peek under the cardboard and see if the leaves are settling. The cardboard can be kept in place with heavy rocks. Snow acts as a cover and protects from the cold temperatures so you can let a certain amount on the cardboard but not much (it may start to bend with time).
To minimize the chance of damage to the stems, do not overfertilize and do not feed late in the growing season. Hydrangeas do not need much fertilizer and you can skip it some years and not notice a thing. Stop applying fertilizers in July so the plant is ready for winter when Fall arrives. In the northern states, you can feed the plant 1/2 cup to 1 cup of manure/compost/cottonseed meal in June. In the southern states, you can feed it twice a year, in May and July because the growing season is longer. But stop all forms of fertilizers around July.
Mulch is also important as it helps the plant have consistently moist soil and protects the roots during winter so keep 3-4" of mulch and check it once or twice a year.
Does this help you?