You only need to prune if the tree is too tall or too wide to suit your needs. Next year all those new branches will set spurs and then fruit in 2013. The new limbs may have some fruit in 2012 and those spurs down lower will bloom for sure next spring.

At any rate your tree is balanced and a good shape. I'd do nothing unless it's too tall.

Here is a link that might be useful: {{gwi:126398}}

Thank you fruitnut! No, I don't feel it's too tall. I am very excited about letting it be- here I thought we were neglecting it by not pruning. I really appreciate the reassurance about its shape, etc. Thanks so much for replying!

I suggest you eliminate some of the vigorous shoots where they are crowding other wood. J.plums grow so rapidly that pruning young trees is very helpful in establishing your permanent shape.

Methely tends to be too lanky and stingy on secondary and tertiary branching. The key is the relative diameter of secondary branches. If at point of attachment they are near the same diameter as the leader of the branch (the one going in the direction you want, therefore the shoot you want to lead the branch) they either need to be removed or stubbed back a couple times during the growing season starting right around bloom. This will slow them down and coax tertiary branching.

The key to training a well balanced tree is to start with a dominant trunk by eliminating all branches more than a third to half its diameter at point of attachment to that trunk and then treat the branches attached to the trunk in the same way (like a more horizontal central leader tree), removing or subduing secondary branches of competing diameter.

These are difficult concepts to sum up in a couple of paragraphs, if you want a detailed article I've written about pruning by ratios e-mail me.

Thanks very much harvestman! Trying to find answers on my own online has been so confusing- your explanation really helps, I feel like I am starting to understand. I am thinking I will let the tree be for the winter as fruitnut said, except perhaps for a couple branches I noticed were crossing each other. In the spring when it's in bloom I will examine branch widths and try to put some of these tips you've given me into practice. I truly appreciate you breaking down the art of pruning into a few basic points, it's a huge help for someone like me with no experience. I've watched all these videos and looked at little diagrams, but realizing there are basic rules to follow about branch widths really cleared things up for me. I'd love to read your article, I will email you.

Don't prune your plum tree in the rain. It is asking for diseases. Stone fruit in general should only be pruned in dry conditions. I pruned my Santa Rosa plum in the rain and got permanent diseases-virii? that I couldn't get rid of. Tree was never the same again.
John S
PDX OR