I just spent the last three hours unpotting some of my largest plumeria (in 18-24" pots), removing the majority of the soil, and have stacked them under a large oak to dry out for a couple of weeks. They have all been cut back so that they are no more than 4-5' tall. I am literally forcing those large plants to go dormant. In a couple of weeks I will remove the remaining leaves, wash off what soil remains, and allow them to re-dry. Then I will bag them in heavy-duty, contractor plastic bags for the remainder of the fall and all winter. They will be bagged for about 4 months, no light, no moisture, and no soil. I will just keep them in an area that will stay above 60 F (probably a guest closet). It will take me another half day to complete this particular chore. I will probably bag up 2-3 dozen plants.
Here's an example of my un-potting a couple of plants in 18" pots. One has most of the soil removed and the other just got lifted from its pot.
