Flower Pot

Flower Pots are required on the Roof levels, because it allows you to plant other plants on top of it, similar to the Lily Pad. Even though it is for planting on the roof, it can still be planted on the ground, but not on Lily Pads for some reason.

Usage
Plant it on the roof, and then put a plant in it. Flower Pots do not have any attacks, and do not have any point outside of the roof levels, but have just slightly above the normal amount of health. To plant any explosives like Cherry Bombs or Doom-shrooms on roof levels, a flower pot is required before hand. If a Doom-shroom detonates on top of it, it is destroyed and a crater appears in the roof. The strongest anti-zombie barrier in the whole game is when you plant a flower pot, a Pumpkin on top of it, and place a Tall-nut inside the Pumpkin. This will hold a zombie for upwards of four minutes, and longer when the zombie is frozen.

Note that you cannot plant Spikeweed or Spikerock in flowerpots.

Strategy
You can use it to slow down Gargantuars in emergencies and to make Pole Vaulting Zombies lose their poles, or to provide a few extra seconds before the zombies get to your defenses, in levels such as Column Like You See 'Em. Apart from that, you just use it to plant on the roof.