I'm not talking about the decoration items. They are pots which can be moved inside/outside of greenhouse/player's own house. By filling it with clay/water, we can plant seeds (no trellis crop)(possible aquatic plants, if CA add them) in it. Currently, I still think that planting trees in the border of Greenhouse, is somewhat insane. I'd rather fill it with those pots - when in an adequate season, we can move it out to save space in Greenhouse, and fill it with other plants.