Vance -
You're pictures have inspired me to acquire a mugo or two... so thanks a lot!
I'm interested in hearing how you generally proceed, year over year, recognizing that the health of the plant tends to dictate what's done. Would you mind sharing what your process is for a newly acquired nursery mugo pine (assuming purchase is made now)? Would you repot in the first summer, how much root mass are you comfortable removing, etc.
Your trees look great. You're obviously treating them right and I'd like to make sure I do the same.
You have to understand from the beginning that I would hunt down a Mugo that may be quite different from anything the majority of first time Mugo growers would come up with. Most of the trees I am shown on the INTERNET, by people asking the questions you are asking, would probably be passed by, in my selection process.
Most of the trees I am shown lack a good sized trunk base that can be a foundation for future development making an initial decision to proceed, in a particular direction other than one to develop stock for future use the only option.
I have a formula or method that I engage in to pick my stock that deserves a separate thread but the bottom line with it is that you have to be able to imagine in your mind what you are feeling with your hands grubbing around under the branches and the soil surface of a nursery grown tree.
As you gain experience in this area you should begin to develop the ability to see in your mind where a particular tree can go---see the future sort of. Most of what I hear from people are thought out styles based on some arbitrary decision that "gee I think this tree might be a good _____?" so I'll go there.
So to more directly answer your question yes, unless there seems to be a problem with the tree that needs to be addressed, by the middle of summer the tree will be into a screen-sided container, pond basket or colander having the soil mass reduced by around 50% and the top pruned enough to encourage what I think at the time the direction of the tree will be.
I'm sorry but I am afraid I have given you more question than answer at this point. Mugos are unlike other Pines you are likely to find and use as bonsai. They are so easily trained into shrubs and small trees that look more like bushes than trees you are not likely to find a Mugo that looks like a traditional Pine tree where their initial appearance says tree. The nursery trade has sheared this guys down into bushes.
