Beautiful landscaping design!

We would be using it on a South (and Ocean) facing lot line wall, needed to add shade for an expanse of glass walls in high-ceiling rooms, which run the width of the home (East to West) and the decks between the trees and the home.

This tree looks like it would allow the ocean breeze to flow through, while providing filtered shade from the all-day sun. It also looks like the trunk is minimal, while able to be perfectly upright; great for this effect.

Adding to the question of zone suitability; are these suitable for Southern California?

Could you confirm the type of tree, please?

And, what age (range) of specimen is best to plant, and about how long would it take to reach the effect of this "hedge in the air"?

Any help with these questions would be much appreciated.

if everyone's guess is right, they are deciduous and good for zones 4 to 8

http://www.monrovia.com/plant-catalog/plants/694/pyramidal-european-hornbeam/

The trees are pleached hornbeam (carpinus betulus). They were planted mature at this size. I'm not sure how many years they have been trained in the nursery, probably at least 3/4 years pleached. Unless you are a fanatic you need to buy these plants pre-pleached unless you are extremely patient and have time on your hands!

Where can you buy pleached trees in the US? I can only find them overseas and I live in Oregon...I love the pleached tree look for a nice privacy screen!

Pleached is the term used commonly in England. Here it is espalier. I'm looking at the same issue for a landscape project next spring that requires making the two story house behind me disappear in a narrow slot between the wall and the pool. Fruit trees are more common subjects here, but talk to your local nursery sources about espaliers and you should do better. I don't know how I am going to create a London John Davies garden in the hills of Los Angeles, but I know I will try.

forgot this link

http://www.latimes.com/la-hm-espalier25a-story.html

also look at espalier on wikipedia. It has lists of appropriate plants/trees.

I am sure you will make it spectacular! You can do this yourself with bamboo but I think it is beyond my abilities!!! I will keep searching I love the clean look and uniformity along with privacy they provide. Good luck.