A tree-pruning-dominant arborist saw me doing shrubs one day, and he said "you are pruning those like the way I do to trees".
Basically, if there is room to grow, the rules on woody shrubs are basically identical.
Shrubs compartmentalize, have a cambium, etc.. They are basically miniature trees.
The issues are that most people cannot afford individual hand cuts for size reduction on shrubs.
Some conifers are forgiving since they will not push buds from under the bark. Yew is one exception.
So we shear azaleas, boxwood, etc. so we don't take advantage of people by "creaming" their budgets.
Rhodies are trees - Rhodo = rose , Dendron = tree. Its name means rose tree. We prune them like trees unless reduction is needed.
If you need to reduce a tree, and do it decently, then apply the same rules to shrubs.
Except the twiggy ones are too severe to waste the time.
Nasty wild things like Forsythia, Quince, etc. we just prune out some of the big stuff to the ground, or cut back to a large node and let it resprout, leaving evenly spaced smaller stuff. Some of these are so unpredictable that proper pruning yeilds no better looks than "butchery with precision".
Look at the Pine on my home page at
www.mdvaden.com
I shear the top of the candles in the spring, then go inside the clumps from underneath and thin some crud. The tree is still gorgeous. It takes about 4 hours. If I did it the full blown Japanese method by cutting and pinching and selecting every shoot, that tree would take 2 days. The owner does not want to spend that much. And there is little difference to the health quality of the 2 methods - its slight.
By the way, that photo is for looks. I hate that kind of pruning. I almost never initiate topiary any more. It always gets more time involved every year, and makes full compensation near impossible many times. A lot of pruners have started many to promote their egos - look how great an artist I am - then taken big hourly base cuts to avoid some migrant coming in after the project time skyrockets.
I used to do a lot of the "cool" stuff until I realized it just fed my ego in most cases.
And its really not that hard to do shapes. Its dot-to-dot drawing with hedge shears. Its where I would start my most primitive employees, comparable to lawn mowing as far as I'm concerned.
As many experienced pruning people know, its learning how to avoid shearing and shaping plants that takes the highest levels of skill and experience.
