Territree

Territree punches anything that comes into its part of the lawn, even plants.

Overview
When a zombie comes into Territree's territory (a 3x3 area around it), it will punch it very fast, like Bonk Choy's Plant Food effect. This will go on until the zombie is either dead or has walked away.

When a plant is planted in the 3x3 area, Territree will punch it away, returning its sun cost to the player, but destroying the plant. If, when Territree is planted, there is a plant in its area, it will punch that plant away like it would if the other plant had been planted on it.

Plant Food Ability
When Plant Food is used on a Territree, it expands its territory to a 5x5 area. Any plants in this area are punched away when the Plant Food is used.

Strategies
A tactic that would work for this would be to have 3 peashooting plants behind 3 Wall-Nuts, then having a Territree two places in front of that. That way, the Zombies wouldn't be able to get out of the Territree's 3x3 area quickly, and the Peashooters would be shooting at the zombies as well.

If you want to use its Plant Food ability, make sure you have space.

Trivia

 * Territree is a portmanteau of territory and trees.