You mention not cutting off the dead wood. If you are getting a lot of dead wood after the winter then the flowerering buds are probably dead also. So you just get a leafy hydrangea bush. My understaning is that Hydrangea macrophylla (except for a few cultuvars) are only reliable bloomers in zone 6 and above. If it's been in the spot six years and never bloomed I would scrap it and try another cultivar. Have you asked your neighbor the name of the type he/she bought?
I live in zone 4 and have the cultivar known as Endless Summer (H. macrophylla 'Bailmer'). It has bloomed every summer (2 out of 2) despite dying nearly to ground level each year and has through -22F. I do give them a good leaf mulch for the winter. They get about 4 hours of afternoon sun and a lot of water. I believe there is another one called All Summer Beauty that is similar to Endless Summer.

Bud damage from winter cold is the most likely scenario for consistently not producing blooms. Mopheads like Nikko Blue and most other macrophyllas are simply not cold tolerant enough to make it through a zone 5 winter without damage to flower buds unless given adequate winter protection. That it bloomed only its first year is pretty strong confirmation of that.

I wouldn't necessarily give up on it but I would review the FAQ's and several of the threads on winterizing macrophyllas to generate flowers for next season. If you are really frustrated, try one of the macs that blooms on both old and new wood that ginkgonut mentions or try one of the very cold hardy paniculatas or arborescens.

they say if your hydrangea is from a greenhouse that is forced and its an EASTER hydrangea?? (you know the ones.... that make ya wanna cry when you see them cuz they are sooooo pretty.) well. I have been told that THOSE DO NOT BLOOM once planted outside.
I have never had one of them bloom either.
I just dug up my Nikkos and replaced them with All Summer Beauty and Endless Summers. Ihad 4 Merritt Supreme and 2 Cardnial reds that NEVER EVER BLOOMED. $ down the drain.And they all had flowers on them when I got them. I am zone 5a. and Iadore hydrangea. My sister is in Goergia. hates them and she has a huge one in her back yard that I would kill for. GO figure.

Nikko's do bloom in zone 5. I had one for years,next to a fence without winter protection. A little aluminum sulfate in a jug of water at the beginning and end of the season, a little miracid through the season and pruning as Karen said. I sold the house and wanted to bring it with me. The endless blooms on the porch and in vases are one of the things the buyer loved. I raised that thing as a baby and still drive by to peek now and then. Have faith. Liz

Zone 5 winters are tremendously different. Nikko Blue is not reliable in all Z5 gardens. A big difference is the amount of snow cover one Z5 garden gets to the next. We reliably have 4-5 feet of snow cover, and Nikko Blue is reliable here. Other Z5s have very little snow cover, and damaging winds. Bud damage from winter is probably the culprit. Try protecting it for winter, or get a variety that blooms on new wood. PS: the Paniculatas are always good choices. Polly

Liz,I love the nikko's and I had one for 5 years without really doing anything much to it and it never bloomed..then i read where you have to totally cover it in the winter..which i finally did and i mean cover it so that not one bit of the stems are exposed and ever since i have had blooms gallor..it is beautiful..but it is work.. and for some it may not be worth it..I also bought an endless summer and last year it was beautiful and did not cover except to put some leaves around base.if it is beautiful again this year that is what i will be switching to but still will not give up on my nikko

I live in the Atlanta area, zone 7, and have 2 hydrangeas that did not bloom last year. This year one has buds, the other does not. Last year I cut off branches during the summer, and started new plants from them. The foliage was thick and healthy, and I thought maybe it was robbing the plant of nutrition for producing flowers, and that is why I cut off branches. I had read on another source if a plant did not bloom 2 years in a row, to pitch it. Any info and advice is appreciated.

So, did it bloom for you in 2006 or 2007?

I have the same problem -- in Zone 7a! A lush, large hydrangea that gets dappled sun and some direct midday sun, and it Will Not Bloom. Bloomed the first year in a pot, never since, and it's been at least five years.

I have a hydranga that is not blooming, I use Holly Tone fertilizer on it twice, spring and end of July. All my other hydranga are blooming like crazy - is there another fertilizer I should use to get it to bloom?

Thank you so much for a response.

Anne