Steve,

Saw that this is still unanswered which is disappointing.

You should not do any major pruning or root work on bonsai until late winter/early spring generally speaking.

Very experienced people can do work mid summer but it is not generally recommended for someone starting out.

Find yourself a good book by Harry Tomlinson or Colin Lewis and read up a bit before you do.

In very general terms a tree has to "grow up" to be chopped down into a bonsai.

Small trees can be designed as very small bonsai (shohin 6-10" or mame

My suggestion to you would be to get the books mentioned, and keep this tree unbothered for the rest of the year and start work in the spring. Junipers can generally be worked on all during the growing season but your comment about keeping it well watered leads me to believe that you need to learn about how these trees react. Read some, or all of the posts on this and other forums concerning water. Some people just starting out are under the misconception that the best way to treat a tree and save a sick tree is with a lot of water. This is the worst thing you can do.

So lets see if you can keep this tree alive through the rest of the year and through the winter. Then at least you will know you have developed a feel for watering.

Vance Wood.