Lawn Mower

Lawn Mowers are your last line of defense in your front yard and backyard. When a zombie gets too close to your house, i.e. past the leftmost column, the lawn mower automatically activates and kills all the zombies in the lane, except when in a Pool row in the back yard, where it kills only zombies that have gotten out of the pool, then sinks into the pool. At the end of the level, you get $50 for each lawn mower left, once zombies start dropping money after Level 1-10.

Strategy
There is not much strategy to them, except to conserve your lawn mowers but to not waste plants to try and (fruitlessly) prevent your lawn mowers from being used up. If it is the last wave, and you have lawn mowers in every row with zombies (and/or the Pool Cleaners and Roof Cleaners), you may win the level. However, it is a bad idea to depend on them as they give you money, along with the Pool Cleaners and Roof Cleaners.

Trivia

 * Lawn mowers are even more powerful than instant kill plants, as they can kill even a Gargantuar in one hit.
 * If you type "trickedout" while playing, your Lawn Mowers change and have a monster truck-like appearance. But it's wheels don't get bigger.
 * The Lawn Mower has three Achievements related to it: Close Shave, Last Mown Standing, and Lawn Mower Man.
 * When a Lawn Mower is activated on a Pool row, it will sink and leave a trail of smoke which will disappear very quickly.
 * When a Lawn Mower meets a zombie, it will slow down. This also happens with Pool Cleaners and Roof Cleaners.
 * When a Lawn Mower kills a zombie, the zombie will only be left with their heads.
 * The only land zombies that will die in a different way instead of being squashed are the Zomboni, the Catapult Zombie, the Zombie Bobsled Team (in their bobsleds), and the Gargantuar.
 * Sometimes, when a Lawn Mower has been activated, the zombies will not enter that lane for a while.
 * Probably it's because the other zombies are scared by the Lawn Mower and stopped attacking for a while. Anyway, this gives the player enough time to recover his plant defenses from that lane.
 * In the online version of Plants Vs. Zombies, Zombies will turn into a puff of smoke once it meets a Lawn Mower.
 * Not all zombies have their mowed animation as being squashed, some turn into puffs of smoke, some get sucked (rarely), some will disappear (on water if you haven't bought the Pool Cleaner). In the Mini-game Heavy Weapon on the Xbox, PS3 and PS Vita version, you will need to control a Lawn Mower with a plant on it in order to shoot zombies.
 * For some reason, the Lawn Mower doesn't hurt plants.
 * Also, real Lawn Mowers cut down grass, but in this game, it doesn't.
 * In Portal Combat, if the Lawn Mower gets into a Portal, it will go to the Portal in the different lane.