I went to several different nurseries today to look at small fruit trees. A
saw one store advertise dwarf, and another advertising an ultra dwarf orange
tree. I believe both were Washington Navel Oranges.
My question is, are they using different terminology for the same type of
tree or is ultra dwarf indeed smaller? I had never heard of ultra dwarf.

I'm looking for the smallest possible tree and am hoping which ever I buy
will grow in the pot I buy it in. My backyard is narrow and I don't have the
room to plant it my soil. Will that work?

Thanks