Kid, are they in commercial nursery containers? In the bay area deciduous trees can be repotted any time after they go really dormant until they pop in the spring. For example, we repotted Japanese Maples in Hayward two weeks ago. But, you know what I am going to say next, get with BIB. Once you get on the mailing list, Boon sends out monthly emails with suggestions of work that can be done that month.