Basically a small mana pool, crafted like vanilla flowerpots, only you can plant floating flowers in them and they can use the pot's mana instead of needing a mana pool nearby. Maybe you can put dirt and non-floating flowers in at the cost of no mana storage as well. Or some combination. Basically just a way to not need a mana pool nearby throwing off symmetry/not need a full dirt block in an otherwise nice floor.