Question
First let me state that I know NOTHING about gardening. My husband and I bought our house 5 years ago and every tree, bush or flower on the property came with it and since I know so little about the care of these things, they have become quite overgrown. The worst case is our hydrangea tree. I assume it is a grafted tree since all the branches come from 1 trunk. My first problem is that we had a central air conditioner installed several years ago and the unit is within 5 ft. of the tree. The tree has started to lean away from it quite drastically. Next, the blossoms of this thing are so big and heavy that they bend the branches to the ground. Is there any way I can safely prune it?

Answer
Hydrangeas have nerves of steel -- but they're not made of it, and if you aren't careful you will kill this plant.

The exhaust from a c/a/c too close to it, blowing at the hottest part of the Summer, can't be good for it.

I don't know where you live, but it is possible you have an own-root Hydrangea that would be quite hardy through the coolest Summer.  It sounds like a very mature specimen that has grown to a substantial size.  If there is any possibility of having this moved -- professionally -- to a more Hydrangea-friendly spot, NOW is the time to do it.

Reason being that Fall is the optimal time for transplanting shrubs.  Roots are receding into dormancy.  They have all Winter to get used to their new underground spaces and recover from the shock of transplant.  This should be done by professionals.  Hydrangeas do best in full Sun, but will tolerate a bit of shade.  The less Sun, the fewer flowers.

As for pruning, you have missed the boat on this for 2007.  If you prune now, you will be removing many of next year's flowers.  As About.com Gardening Expert Marie Iannotti points out, 'Bigleaf type hydrangea set their flower buds at the ends of the upright or lateral branches, during late summer to early fall. Pruning Bigleaf hydrangea in the spring or even late fall, after the buds have been set, will remove the flower buds and any chance of getting flowers that season.'

Bottom line: NO PRUNING!  Do that in 2008, mid-July.

The huge flowers you are getting on this shrub are wonderful.  Remember this shrub naturally grows big, beautiful flowers.  Pruning will help somewhat, and strong Sun will shorten the stems a little, but sometimes the best thing you can do is cut them for bouquets so they don't drag in the mud after a Summer storm.  Keep a good thing going.  Move it somewhere Sunny and Open, where it has a future.  And get a pro to do the honors.

Thanks for writing.