I have box trees in pots which I have been trying to shape to what the Japanese call "Clouds" without any success whatever. The shrubs have been in the same pots for 8 years and are still green and look very healthy but, weather permitting , I am going to put them in the garden, "set them free" as my husband says , and hope to continue training them. I have found that box can withstand neglect and going without water for ages without seeming to come to any harm.