James, Yes, they are slow going. Eventually you will have to nuke it with fertilizer, albeit in smaller doses for a tree tat size. My 5 gallon size tree, after being in ground for about 4-5 years, and growing about 1-2" a year, got about 15-20 pounds of triple-15 fertilizer one season, and I got 4-6 of growth. The following season it grew about 8' and was a grower ever since. I figured I had nothing to lose. if it died, I wasn't out much since I wasn't getting much from it. Put yours on a miracle grow regimen and feed ti every week.
Even when I do air-layers, I put them in the greenhouse all winter to keep them alive, and the following spring they can take off and grow.