ABSOLUTELY nothing to do with bonsai . . .

. . . but stunning. There are several pages. Click and enjoy.

http://www.clarklittlephotography.com/gallery/gallery/3-0-MainGallery.html

Awesome photos! Makes me miss being by the ocean.

I was there the last week of July. Really beautiful and you can't beat the weather, unless you like cold and snow and etc.

I believe I should open my question with an apology. My questions are not exactly for Bonsai trees, but I am hoping you can answer it anyway since this group are Meisters in tree pruning/sculpturing. I will fully understand if this question is immediately deleted and the leaves are ripped off my branches. If that is the case, I will tuck-in my trunk and rot away. If this is the case, I apologize for wasting the Forum's time.

My problem-
I planted a couple dozen Thuja Occidentalis in May (2012) for a privacy hedge. I live in Western Germany, next to France. I planted the 1 meter high trees 60cm apart (trunk centered). At this point they have been in the ground for about 6 months. Most of the plants have grown an additional 30-50cm.

My questions are:

1. When should I cut them for the first time? Do I let them have a full season to grow before trimming them?
   
   
2. For their first cut, should I cut them all to be the same height (therefore, the shortest tree determines the height of all the others)?
   
   
3. When should I cut the sides (between trees)? Before the branches touch? After they touch? Never?
   

Thank you in advance for any help you can provide.

When should I cut them for the first time? Do I let them have a full season to grow before trimming them?

For their first cut, should I cut them all to be the same height (therefore, the shortest tree determines the height of all the others)?

When should I cut the sides (between trees)? Before the branches touch? After they touch? Never?

I would wait until the beginning of your Spring.

If you let the weaker ones grow they might get stronger, so I think I would cut for shape and to encourage growth. Pruning will encourage fuller growth down lower.

If you want the sides to touch, don't prune, if you want space for light and air, you should prune for shape.

Did you plant the species or a named cultivar? If you planted the species, you know they will grow into giant trees and throw cones all over the ground. If you want a huge windbreak, leave them there and pull out every other one at least. If you want an attractive, shapely, seedless, moderate sized hedge, around 4-5 meters, you plant one of the named cultivars. I have a row of 'Smaragd,' a very nice cultivar. After 15 years, they are about 3 meters high. You don't prune them at all. They eventually touch each other and the tops are neat round spires. They are never all exactly the same height, but so what?
Iris

You typically let Thuja grow until you are certain they have taken (Which they now have, with 30cm growth). I usually trim my hedges twice a year: Late summer (Late August, Early September), which allows the tree to recover & create new growing tips before winter hits, and right after the big spring spurt, roughly in June. You cut these when a few clouded days are expected; Otherwise you run the risk of browning of the cuts.

You would cut the tips of the trees as soon as they reach about 30, 40 cm below the desired height. That would stimulate filling of the lower potions. Remember that you cannot cut Thuja back once the branches have browned: Only green shoots send out new foliage (!). This mean that also the front and back of the tree (The side facing your garden and the side facing the outside of the garden) should be trimmed as soon as you get close to the desired with of the trees. Typically you want the hedge to be fairly narrow; Letting it grow wider is easy. Getting it more narrow is virtually impossible once branches start to brown of.

So: I would start trimming the hedge clipping all the parts that are growing within 10-20 cm of the range you want the hedge to be in the future, leaving a bit more space on top, increasing the size every time you trim untill you roughly have the size you want. The sides of the trees will grow into the tree next to it by itself. No need to trim in between trees (But you could trim them if you think it looks better; Remember it will slow down the closing of the hedge. Make sure you trim the hedge a little narrower on the top than below. This allows light to reach the lower branches, ensuring a green hedge from ground level up. Also, don't plant anything too close to the hedge, or the lower part will die off due to lack of light.