Dwarf tree fruits are not usually as 'dwarf' as people think they are and generally aren't a great choice for container gardening. Also, tree fruits such as apples, peaches and cherries grown in our area are prone to diseases and pests that need close management and carefully timed and repeated pesticide sprays for satisfactory fruit.

For your dwarf peach, our specialist thinks that you will need a much bigger pot, along the lines of a 25 gallon container, at minimum.  We suggest using a half of soil-less mix and half of compost (or Leaf-Gro, which is made locally). (You could use all soil-less mix if preferred). 

We tend to think that now is not the best time to re-pot, but would wait for when the tree is dormant.

We don't have the research on any new cultivars but if you would like to share a named variety we'd be happy to take a look.

Christine

You're welcome.