Usual recommendation is to remove the soil from the whole and mix with a combo of garden soil (NOT potting mix), humus, compost, peat and bone meal (IMHO). Your ratio should be 50-50. In zone 5a you would probably want to burry the bud union at least 2", but I'll let those that live in your area/zone weigh in on that.

I am thoroughly disgusted with peat. It breaks down, compresses, rapidly decomposes into a solid rock like substance unless large amounts of vermiculite and perlite are added, and that makes it extremely difficult to maintain moisture in the pots. I am watering everyday and sometimes need to water twice a day. Wick watering is not an option because of how I display my plants and also because of rapid evaporation. I need a heavier soil that does not retain moisture like peat does. Peat also is devoid of any nutrients, does not retain nutrients so fertilizing is more the art of hydroponics rather than soil based science. I don't have garden loam this being Arizona rock and sand desert soil. Any suggestions? I can get well rotted manure, blood meal, bone meal. Anything else necessary?

Help!!!

Yep one thing I learned at the end of some growing seasons, was that the plant I thought would fill up the pot with roots just barely had a small rootball, not worth putting it in such a large pot. So as Nick said, knowing that may help you save some soil. This is why some pots with various plants in arrangement look so great, because you would think the roots are all competing with each other, but in fact, they are growing at different depths or different areas of the pot, not really growing into the entire pot. I have used the techniques of putting stuff into the large pots, or even growing smaller pots in a larger pot, and you can replace the smaller pot with any plant in a similar pot whenever you want. I really recommend that method if soil quantity is a concern. At the same time, you have the beginnings of a good soil mix. The leaves may not be at the right stage for being about 1/3 of your potting mix, but you can also get some bags of compost and mix it with what you have. If the leaves have composted to the fine dirt look, it's good, but if it is still in some rotting stage, it might not be. There are also more topics on what kind of pot soil is good, but you can learn more on that as you go.