Hi everyone! This is my first post to any bonsai forum ever!
So i woke up this morning with a question that comes from my dearest treasure, a book my grandmother gave to me when I was 10 called "Miniature Trees and Landscapes" by Yuji Yoshimura and Giovanna M. Halford. The book is intense, to say the least, and it got me started on my bonsai journey.
The question I have has to do with drastic pruning. The book says: "Once they are full grown, evergreens, such as juniper, pine, cryptomeria, spruce, and cypress, cannot stand drastic pruning. Any alteration to their shape must be done by wiring and trimming only. Deciduous trees, on the other hand, will survive very drastic treatment."
I bought quite a large Buxus bush from a nursery because it's nebari and taper are excellent, but it needs drastic pruning. What exactly is meant by "well-established", and is he referring to all evergreens or only the coniferous types? Mr. Yoshimura has trees that are 500 yrs old, and i doubt my new tree can be more than 10 years old. Can anyone weigh in please? Can I give my Box a drastic pruning, or should it be done gradually? Also im currently in early spring. Thanks in advance.

for most evergreens you can remove up to half of the foliage in one go. Boxwood can take a bit more. But ensure you do not trim beyond the last leaves on a branch or you run the risk of loosing the branch. Not all species of box build new buds after trimming past the foliage.

Last time I pruned and repotted a Boxwood, it died on me.
In early spring.
Well, it WAS drastic alright, I guess too drastic for the box.

My very first tree was an azalea. I put it in a pot and cut a few branches off, but could not bring myself to cut much off.

One night the neighbor's cat came over and sharpened his claws on the azalea. My typical nursery shape azalea overnight became a windswept design with maybe 20% foliage left. Radically different design and really ambitious cut. That tree lived for a long time and was really pretty.

I have cut lots off myself and not had the same luck. I wish I could get that cat.

Ivan Mann wrote: My very first tree was an azalea. I put it in a pot and cut a few branches off, but could not bring myself to cut much off.

One night the neighbor's cat came over and sharpened his claws on the azalea. My typical nursery shape azalea overnight became a windswept design with maybe 20% foliage left. Radically different design and really ambitious cut. That tree lived for a long time and was really pretty.

Box and azalea are VERY different plants. What you can do to aalea will kill boxwood.