If you have a gardening friend that has a digging fork that works best. If using a spade (or a fork) loosen the earth beginning about 18" out and feel for roots, that is resistance when pushing the tool into the earth. The tool will go into the earth at some rate and stop when it comes to a root it can't cut easily. The fork has less surface and therefore less to stop on a root, often just deflecting past. Stepping on the shovel with both feet and moving it back and forth sideways may slice through, or you may have to remove enough earth to get a cutting tool to the root. When the tool is all the way down, wiggle it back and forth and sideways breaking/softening up the soil. If you're lucky the plant will move, too, telling you that it is not fixed by many roots in many directions. Do that all the way around the plant, hopefully loosening it a little from each direction. Eventually you should be able to pull the tool down to force the plant to rise up and be free. There will be substantial roots going in several directions that have to be chopped off with the shovel or a loping shear or cutters of some kind. If the soil is hard packed, or clay, or both, it will take longer and more effort, but eventually you'll have a rootball that you wash the dirt off with a garden hose to have just the roots. Since you have more than one individual (I speculate) you have the opportunity of pulling them apart, carefully. Keep the tiny rootlets that do all the feeding wet, and reduce the heavy anchor roots to suit potting up. Some of the big roots will go out a long way from the plants. Chop at some distance from the trunk that you know will not be useful in potting up.
@Shibui is the only one with experience with these, so you can photo the whole masterpiece after washing, put it into a garbage bag wet, seal it tight, keep it damp in a dark or at least cool place, and get final instructions.