If they bloom on OLD wood then the buds were probably hit by the record cold temps these past two winters. Where are you Ken? Here in Jersey we had the coldest winter I can remember this year. I am winter protecting mine from now on so this doesn't happen.

Because my winters are usually mild like yours, I never winter protect but, I got 'hit' during the last two winters. It seems as if every 7 years or so, we get this issue down here too but the last two winters in a row were just bad. Winter 2013-2014 was worse than last winter. Only by winter protecting can you be sure that this will not occur to old wood varieties.

The problem arises when the temperatures fluctuate up and down, causing the shrub to break dormancy just as the temperatures are about to plummet again. The flower buds then get zapped.

This year... I have an unnamed mac, a MEM, a paniculata and an oakleaf that they all did all kinds of things in the north side of the house: unnamed mac #1
had exactly one bloom; unnamed mac #2 had no blooms; the paniculata
(blooms on new wood) is starting to bloom; MEM is blooming as if nothing
happened; the oakleaf hydrangea did not bloom. Of the macs, I can
usually count on old-wood MEM (Madame Emile Moulliere) to bloom. Awesome shrub and I am very pleased with the purchase. This year, it
looks normal, bloom-wise, and in 2013-14, it had reduced bloomage but at least it had some.

Other macs and oakleaf hydrangeas plantyed elsewhere in more "protected" locations bloomed normally.

So, do not despair, be aware of the impact of temp fluctuations, water the night before temps are expected to crash and consider either adding remontant or new wood varieties for these bad years. Remontant ones will not bloom early in Spring though, later like late June or July-ish. And consider monitoring the weather in winter and adding winter protection late (in mid-winter) if you detect this temp issue coming up. I probably will take no action to protect. Maybe.

Nothing blooms on dead wood :-) Most bigleaf hydrangeas bloom on old wood or at least second season growth. Some - like Endless Summer - bloom on both new and old growth.

Winter or late spring cold weather, improper pruning and excessive high N fertilization can all affect flowering. As the eastern half of the country has experienced two successive cold winters, I'd suspect that is the primary cause of lack of bloom and the winter protecting, as suggested above, may be the best solution.

Even here on Vancouver Island where the winters usually don't get severe I always leave the old flower heads on until the following spring, just a bit of added protection. Last spring we cut back a hydrangea that had out grown it's spot, we selected the canes we wanted to keep and cut the others out. Had a nicely shaped shrub by the end of summer. We had an unexpected hard freeze the beginning of November, the only hard freeze we had all winter, this spring we had to cut back by 1/3 to get to live wood, so again no flowers this year. This fall it's going to be wrapped in burlap in hopes this will do the trick and it blooms again next year.
Annette

2 bad winters in a row had blooms only a few select varieties and this year many were hurt and the tender ones no bloom so do not despair!

Real bummer. Thanks to all for the information. Maybe the cold winter also affected by climbing hydrangea...which has NEVER bloomed since I got it as a small three foot vine five years ago. I know those buggers take time...but...in my lifetime...please

For some reason it's not as leafy this year, yet it wants to keep climbing higher...about 40 feet on a poplar tree. Maybe it's looking for sunshine? It does get dappled sun/shade.

Plant maturity helps too, like a good root system to support stem survival. Plastic wind breaks also DO help immensely. 2015 winter here was nearly as bad as 14, but not quite. And as already mentioned, from what I've seen, stem survival is even more critical than bud survival. This year, on countless plants the buds started to green up and then stopped and died - this is because the stems had been damaged and the plant needed time to decide to keep it or not.

Conclusion: if you can get the STEMS to sruvive, then blooming won't be an issue.

Some macs' stems are much easier to protect than others. And of course not all were created equal. You insulate one plant and the stems stay nice and tan with green buds, while on another you do the same and it all just rots.

Just another thought. I noticed a neighbor's lacecap or Serrata blooming like crazy. He did not winter protect. I'm going to try one of them. All I've read say they are more hardy.

Yeah, climbing hydrangea will usually wait until it reaches the top before starting to bloom profusely. Just make sure you do not over-do the nitrogen while trying to make it reach the top... in this lifetime. ;o)

For my ES Originals in the ground, all I did was (accidently....as I had extra compost left at the end of the season) put about 6 inches of compost on the crown of the plant. I had a lot of die back above the 6 inches but those buds that were under the compost all survived and now have flower buds on them...

I just bought a straw vanilla hyd on thurs. 90% of the leaves are dried up and fell off. It is still in the pot and I have watered it every day and it is in the sun. Any thoughts?

I think watering everyday could be too much unless you are in the south and your hydrangea is still in the nursery pot. I'm in Texas and find that plants that I bought from the nursery tend to need watering everyday because the growing medium is very very well drained.

I got my latest Paniculatas in the ground immediately and didn't even water them, mainly because there's been about 6 inches of rain here in the last two weeks. If you do that, just make sure they aren't in an area that accumulates too much water just below the soil line. Also the crowns can be kept a bit above ground as they are hardier and don't need as much water as their cousins.

Chris, is it in a black pot in the sun? If so, the heat generated on the black pot could be frying the roots. Get that thing in partial shade and inspect the roots, it may need a better pot/spot while you are waiting to plant.

Also recommend placing pots on soft ground or grass, and not artificial surfaces like tiles or pavement. I Have a 3-gallon Abracadabra Orb that was on a concrete tile for 48 hours with no water, and it completely wilted while four of its brethren on grass right next to it were fine. And this was in mostly shade.

Are you saying the top of the tree Luis? That's another 30 feet.

No, it doesn't need to reach the top of the tree it is climbing on before blooming :-) But climbing hydrangeas do need to reach a certain stage of maturity to produce flowers - and that is the concept underlying the need for a period of establishment for these plants before expecting flowers. Typically, flowering maturity is achieved in the plant's 7th-10th year, so I'd expect you to see flowers soon.

You can shortcut this extended waiting period by purchasing larger, more developed plants to begin with - the larger the plant initially, the closer it is to reaching flowering maturity.

On another note I had a Schizophragma planted in supposedly ideal conditions, it never bloomed so after 17 years it got shovel pruned. Beautiful foliage covering the side of my lath house but nary a flower in all those years.
Annette