Here's another strategy. Dig down on two of the four sides of the rootball of each shrub to sever half the roots (this promotes new feeder roots close in). This can be done now. Refill the excavated area with the native soil, trim back the top growth a little bit and make sure the plants get frequent watering during the summer and fall.
When you decide to collect them (prior to next years growth spurt), complete the excavation of the other two sides and redig the original two sides of each plant. Make sure you have containers and repotting soil ready before you lift the plants.
The sketch below illustrates the procedure.