You appear to have some very nice hydrangea macrophyllas. Because their size is causing a problem, I agree with your decision to prune.

Most of these hydrangeas bloom on old woodand now is an excellent time to do pruning: they produce flower buds for spring 2008 in August 2007. Pruning now will therefore not affect flower buds because they have not developed yet.

Some pruning is usually recommended every 5 years or so during a three year period. On year 1, you prune the oldest third of stems. On year 2, you prune out the next third. And on year 3, you prune the remaining ones.

You may want to also consider transplanting if this will be a problem frequently. In either case, hydrangeas and azaleas are best transplanted when they are dormant. I tend to move my azaleas during winter because my fall weather temperatures fluctuate a lot and I am never sure if these evergreen bushes have reached dormancy.

Luis

Nancy, Nancy, Nancy.....Everything Luis wrote above is factually correct. HOWEVER.....(I am writing only as a conscientious objecter) You have the hydrangea bushes that we all dream of having. They are gorgeous and mature and blooming very well. They are of perfect scale in front of the deck foundation and did I mention that they are GORGEOUS? Why not move the Azalea instead? It breaks my heart that you would even condsider bringing the pruning shears anywhere close to those beauties!! (ok..guilt trip over, it is , after all, your yard.)

In answer to your other question...They are all macrophyllas although the exact cultivars are hard to say and may never be known for sure. Care and treatment for all should be about the same anyway. Since you are new at this, I have included a link to hydrangeashydrangeas.com. It is an excellent site in which to take a quick tutorial about hydrangeas and the (please don't) pruning of same.

Begging you to reconsider.....yg

Here is a link that might be useful: hydrangeashydrangeas.com

If it would be me, I wouldn't touch the hydrangeas, but would rather found appropriate place for azalea.
They'll be the same size in a matter of a year, max two and azalea still have no room to grow.

YG 15:34 -move azalea,
Ego45 15:35 - move azalea.
LOL

Brilliant minds think alike George!!!....yg

YG & ego...your suggestion makes perfect sense, thank you. i won't prune them and instead i'll move the azalea. you're right, i'm new to this and i *thought* the azaleas were looking overgrown, but what the heck do I know, lol!

the woman who lived here before me and planted the hydrangeas was very attached to her garden and spent a lot of time tending to it. I'm sure she will be happy to know that I'm taking your advice and NOT pruning them.

Thank you for the link!

Glad to hear it.
I know I'll sleep better tonight!! (lol)....yg

Oh my goodness - I wouldn't touch those plants! They are as YG and Ego stated, the kind I would LOVE to have. Please move the azalea!