The apprenticeship is going great! Dan has 2 eastern white cedars, I'll be sure to get some photos of them tomorrow when I go to the garden for this thread. I thought by now I might have photos of every tree in his garden, but I guess I did not! For our area, he has far more Pacific Red Cedars (also a Thuja genus member) and Alaska Yellow Cedar (related genus). We see white cedars here in landscapes plenty though, but those yamadori around the great lakes there look amazing. Totally different from the bog western cedars we find here. Honestly, I haven't pruned any whites yet, but I've done reds and yellows and hinokis following the same general principle. It is true that they need painstaking fine wiring to be improved further, but for these western species, the rate of foliar growth is not too fast if root space is confined. I have found on the cedars I collected last fall that if they are given new root space, they will certainly take off in growth though. Alaska yellows have the added advantage of having a more profound wilting tendency once their fronds grow larger.
Anyways, here are 3 Alaska yellow cedars I have worked on this year for now. The first I helped Dan clean and prune lightly before loaning it for display at the
Pacific Bonsai Museum's "Natives" exhibit back in April, ending in October. The second is an Alaska yellow cedar that I pruned harshly (~16 hours) in July and is now bouncing back. That one is affectionately called "The Wraith." The third is an Alaska yellow I pruned over 20 hours and 3 weeks and just finished
last week (please excuse my shameless plug).
These Alaska yellow cedars are pruned about once every 3-5 years, depending on the density and rate of growth. The pruning is a little bit like a fractal. The most simple situation is there is a complete central frond like a Christmas tree with side shoots in opposite fashion that appear as smaller fronds. When pruning for ramification, I take out the central frond at the distance that I want the branch to change direction. I repeat this on the smaller ones. Obviously this would entail taking more off for a longer, vigorous shoot than for a smaller or less vigorous shoot. My mentality was very much clip-and-grow oriented in exercising this method. I intend to make a youtube video about the subject in the future as I got some film from my pruning last week, but I have not yet started that endeavor. Hopefully all this will be helpful to someone!