Hibiscus in Langley BC

Hi we have a very hardy white hibiscus in our south facing front yard and would love to transplant it. (It has overgrown our walkway). Is it too early in the year (Jan) to transplant it? Also the area we are thinking of transplanting it to is right by a well established Maple tree, will the soil be too sweet? Or should we put it in a pot? (if we do pot it, what rule is there for deciding what size of pot to use?). Thanks kindly, Katrina (inexperienced in the garden) :)

PS. any hints/advice on how to trim back an overgrown Japanese Maple?