You're talking about the old blue mophead type? If so, don't prune them until late spring, late april would be a safe time. They bloom on old wood and even a minor trim of this years growth in fall will cause the whole stem to die over the winter. They drive my wife crazy because they are so big by autumn. Just leave them alone and they should flower next year.

I wouldn't prune them at all for now. I assume yours are not overgrown after one year in place. Just take out what is dead in the spring. And be careful doing this. Some branches look dead but are not. The real white sticks are dead. Check for green centers. This is the first year some of my hydrangea macrophyllas bloomed. I bought my plants very small 4 to 5 years ago and it was worth the wait. I almost gave them all away except that I think the foliage alone is beautiful. Glad I didn't.
Since you just planted yours last year, I would give your plants a little time to establish, maybe up to three years. And as Wardw said, they bloom on old wood, so the buds have to make it through the winter. I find that they break dormancy very easily so I lost most of the terminal buds to warm winter spells. A week of warm weather would cause them to start opening. Once the weather turned cold again, they would freeze. No flowers. Last winter was consistantly cold, so all worked out for most plants. If you go on the hydrangea forum, you will see some people go through a bit of trouble to overwinter their hydrangeas.
Additionally, if you have a warm early spring, keep an eye on the dryness of the soil because they break dormancy early. I lost buds on one of my plants because of this once.
One more. I did say they break dormancy early. That being said, as you move down the branch, it may take longer. My plants often like to put their energy into the basal buds first, sending up new branches. Unfortunately, those won't flower this year. Once this happens, it may get to breaking more buds on the old sticks and those will flower.
What kind do you have?
Oakleafs also form their flower buds the year before. You can see their flower buds when they go dormant. They can be damaged from the cold and die back, especially new plants. But they won't break dormancy during winter for me.
Hydrangea grandiflora blooms on new wood and so does Annabelle H. arborescens so they can be pruned in the spring. The new H. mac Endless Summer is suppose to bloom on new wood. It is a break through plant.

Here is a link that might be useful: overwintering hydrangea

Hi
I am also a newbie to hydrangeas. I would suggest you try the hydrangea forum. They are all very informed as to the care and feeding of hydrangeas and are very willing to share their knowledge.
Pat

I find mine to flower best with horse manure and seaweed. Last year I skipped this and did not have blooms. They are beautiful and blooming this year, thanks to compost.

So Sugar Magnolia, you never did say for sure if these were H. macrophylla.
One question is, did your magnolia grow back from the base or did the branches from the previous year leaf out? If so, how far down the stick did the first bud break?

Hi all -- Thanks -- there is much good information here and I appreicate all the feedback. I've got many different hydrangea varieites. I'd have to go back and look at all the tags to give you an accurate report but I'll do my best from memory. The tags are downstairs, I am upstairs in bed.

There are several macrophylla, nikko blue, oakleaf, lady in red, mopheads, climbing hydrangea... probably others I am leaving out. Let's see, one climbing hydrangea had much new growth but no flowers... nothing dead, plant looks great, just no flowers. Another climber showeed slow growth and no flowers. A third climber was moved this Spring and is in shock; it is withering and I hope it survives. I need to move one of the other two climbers this season.

Three of the four nikkos died. The one that survived looked like a few sticks in the ground although it was a big beautiful plant when I put it in:-( I cut it back in the spring and it grew leaves but often looks wilted/droopy... no flowers

Lady in red and five mopheads are new in my garden this year. Damn!!! I've already cut the dead flowers off three of them.

Macrophylla... one just bloomed a couple of flowers in the last week or two. The others didn't bloom and look pretty wilted.

I cut what seemed to be dead wood in the Spring -- the stuff was pretty dry so I am fairly confident it was dead. And some of it was definately white but I can't recall if all of it was. Some plants just leafed out from what was left after I cut them back but there is a wee bit of new growth at the base on a few.

Most of the hydrangeas that are wilted or scrawney are in deep shade under a huge Maple. I wonder if it's too much shade or if the Maple is sucking all the nutrients from the soil or if they aren't getting enough water. It seems when I saturate them they pick up -- but still no flowers.

Most maples consume huge amounts of water. I've heard, on the hosta forum, that watering the maples will help out anything under them. Watering just the plants makes the maple increase roots in the watered area, choking the plants. I am not sure hydrangeas like the deep shape. Mine are in partial shade.

I know they love water, and I know I have to water when they do not perk up in the evenings. I have no idea what kind I have, but all I do is put a good pine needle mulch on them in the fall for those blue/purple flowers. Other than that, and water when needed, I neglect them, and they love it.

I have only one climbing hydrangea, and it is supposed to be slow to grow and bloom, so be patient.

You have a great collection, so let us know how you make out.

As far as climbing hydrangea is concerned - Hydrangea anomala subsp. petiolaris - that is totally different. I have heard the plant can take up to five years to start showing some good growth once it is in place. My plant is slow to establish. Granted is was in a lousy spot under another plant for the first three years before I move it to its place and I bought a rooted cutting really. It will also take many years to flower. It is suppose to climb first before it flowers so if your support is shorter, it will take less time to flower. Since I sent mine up a huge hickory tree, I might be quite old before I see anything.

Hydrangeas wilt easily. Mine wilt all the time and are a good indicator plant in the garden when it needs water. I always give them extra water. It helps to water more deeply than often. Additionally, it has been extra dry this summer.

Also my hydrangeas flowered in shade, even in deep shade under an oak but maples are tough. My plants that can live under a maple are much smaller, harder to keep alive. The canopy keeps it pretty dry in the rain and if the canopy is low, it might even block a sprinkler. Mine did until we had it heightened. That helped. I don't think hand watering is good enough here. I don't think it will penetrate down deep enough. Soakers might be an answer. The maple roots are shallow and will invade everything. I would move those hydrangeas if possible at least 15- 20' away from the trunk. I have a pee gee Brussel's lace about 20' from a huge maple. It flowers but isn't its best here.
I think you might be OK with deadheading after flowering. Those tips will die back naturally anyway. Just keep the stem though. I really never deadhead until next spring. I find the winter winds do the job for me. I don't mind the faded flowers. Plus a cut stem is an invitation to stem borers. If you see holes in the pith of your stems come winter, you have them.
The nikko can still come back strong. You cut it back so it would not have flowered this season.
The oakleaf is easier. You may still lose some flowerbuds to the winter but every year, it will form more and more.

I added too much vinegar to my beautiful Big Blue hydrangea. It lost all of its flowers and foliage, and the stems promptly turned brown! Now some leaves are coming in(very few) and I have a few new green stems. I do however have a majority of brown stems what should I/Can I do to rejuvenate my plant???

Vinegar acts as an herbicide because it has such a low PH. The only thing that might help is heavy waterings to wash it away. There is still time for it to recover and put out new stems so it will flower next year.