If your expectation was to get a plant, then that's not how it works ;)
Empty Flower Pots once contained a plant, but they weren't maintained properly and died, there's nothing more you can do with this item. In order to receive a Flower Pot that can turn into a fully grown plant, you need to trade 5 seeds with NPC Rosemarie in Port Hope. This can only be done during the Flowers month - June. It takes several days to turn a flower pot into a fully grown plant, if you remember to water it often enough.