Gordon, sure the cake is edible. Stacked cakes, like wedding cakes, have dowels keeping the top layers from sinking down into the layer below and each layer is placed on a cardboard round. You just cut each layer separately and remove the dowels as you go. These are new, clean dowels made by cake suppliers for cakes. No problem. The sparklers don't touch the cake other than where they are pushed in and the paper cup "nose cone" would be taken off before the rocket body cake was eaten. Thanks, Tropic. I didn't do what you have described and I'm wondering now if you think I should unpot it and work harder at loosening the roots. Please let me know what you would do if it were your plant.