QuestionsHow to growTrees and ShrubsPlantingtransplanting acers 0 Vote Up Vote Down Fintan Hession asked 14 years ago When is the best time to transplant a Japanese maple to a new or bigger pot/container? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago If it is being transplanted from one pot to another, that can be done any time, in theory, but it is best done when the tree is dormant. If it is still in the open ground, it is best now left until autumn.