Thanks Luis! Your post made me realize that we would not be able to refinish or apply any protectant to the wood through the years which would no doubt degrade the the wood faster.

The other idea we talked about was building a huge, sturdy trellis. This would have less ornamental value and would only serve to support a hydrangea. I think I would be ok with the risk there since it would not serve any other purpose.

What happens to a hydrangea that gets to the end (top) of a trellis? Will it just climb down the other side?

Thanks for the tip about blooming on old wood; I'll keep that mind. I don't expect to see blooms for several years. But it has such attractive leaves and pretty exfoliating bark that the flowers are just the cherry on top for me :-)

Greenhearted, don't plant one near the dog run, as hydrangeas are toxic to dogs (and cats and horses).http://www.gardenguides.com/90557-hydrangea-plants-dogs.html

Appreciate the warning vasue! The dog run is not used by our dog (built by previous owners), and were it not for the poured concrete floor, I'm sure we would have taken it down by now. My dog is a timid thing so she doesn't wander much and "gardens" with me all the time. I have yet to see her try and eat any plants. I will definitely keep an eye on her and if she shows any inclination, I'll give the hydrangea away.

I hate to rain on your parade but I don't think either structure is very suitable for a climbing hydrangea. You could probably train it over the dog run but depending on how structurally secure that is, it could very well crush it. The weight would certainly impact any roof or cover the run might have.

And the trellis structure would work only for a short time. These get to be massive plants - 50-60' in time - and the need to prune it often to keep it confined to just the trellis would not allow the climber to maximize its potential, as well as limiting any flower display.

Climbing hydrangeas attach themselves to surfaces with root hairs that emerge along the stems. They really need a wide, more or less flat and rough textured surface to accomplish this properly. Like growing up a brick wall or chimney. Or up the rough trunk of a large tree. Even growing up the fissured, barky trunk of my Douglas fir, strong winds could dislodge the climbing stems.

I wouldn't worry about the dog :-) I have always had dogs, often more than one and sometimes puppies, and had dozens of different types of hydrangeas. The dogs have never shown any interest in them. FWIW, more plants in our gardens are toxic to both us and our pets to some degree that those that have no toxic properties. It's not really an issue of concern.

Thanks gardengal! You are not raining on my parade at all; this is exactly why I posted here since I have no experience with this beast -- er, plant.

How much growth per year are we talking here? (Once established and happy)

Once established - and that can take some time with a climbing hydrangea - you can expect around foot or so a year. Maybe a bit more if good soil and well-sited. In fact, it seems to grow progressively faster the longer it has been established.

I have one growing on the south side of my house and it seems to grow onto itself , almost as if it's protecting itself. The one on the north side of the house is truly magnificent. It spreads it branches out and up, the leaves are so much bigger both bloom extremely well from soil level all the way up. Both are growing on a 2 storey brick home. North side is almost at roof and about 18 feet wide (?). They are both 27 years old. Parts have blown down twice. My husband put in nails and stretched thick copper wire across the plant in several spots going up to prevent it coming down again. So far it seems to work well.

Thanks for the information gardengal. It seems like, based on yours and others' experience, that this plant is very vigorous once established but not aggressive.

Elizabeth, your plants sound absolutely lovely! How interesting that the leaves are significantly different sizes based on the sun exposure. Thanks for chiming in with your experience.

Yesterday, my husband and I took down a medium size tree that the original homeowner had planted in a bad spot. The top was leaning over trying to get sunlight and had a lot of dieback. The trunk was quite straight and split into two trunks at about 6' high. After we cut off the upper branches, my husband was suddenly inspired to make a lean-to type structure for the hydrangea and notched out the V made by the trunk split and took the thickest of the two upper trunks and angled it in into the V. The trunks are a good 8" in diameter so they will last a long while before rotting. We'll put in some smaller branches for the hydrangea to establish itself on and hopefully, since this one will be in more sun, it will grow onto itself like Elizabeth's.

The structure is not that big, but there is a large tree just behind it (which is why the other tree was struggling so much). So if/when the hydrangea engulfs the lean-to, hopefully we can train it along the ground and up the tree. We'll see how it goes. I will try to post a picture.

We will put the other one on the chain link dog pen using the biggest branches from the tree as support to give it something to climb. This one will be in a lot of shade. I have a book by the Royal Horticultural Society on pruning and training and it says that Hydrangea anomala subsp. petiolaris does very well with a hard pruning. Of course, we'd loose blooms for a while but its good to know that this plant can handle it if need be.