I have several tree roses planted in a planter box. Some of them have sunk 2-3 inches. I need to "level" the soil to have a uniform surface. Rather than dig up the roses, can I just add more dirt around their base? I know with trees this is not a good idea. Does the same rule apply to roses? If I have to dig them up to raise them, should I wait until they are more dormant? Thanks for your responses.

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