It is based on the machine in real life with the same name.
Its description references its use in the Plants vs. Zombies series, where it can instantly kill all zombies in its lane as a last line of defense, including Gargantuars.
It being unplayable on the heights and aquatic lanes is probably due to the existence of Pool Cleaners and Roof Cleaners, which replace Lawn Mowers in Pool, Fog, and Roof levels in Plants vs. Zombies. It may also be that way due to Lawn Mowers not working properly in said levels.
Statistics
Class: Solar
Tribe: Trick
Ability: Destroy a Zombie on the Ground.
Set - Rarity: Premium - Rare
Card description
The thing of Zombie nightmares.
Strategies
With
Lawnmower is a very useful card to have, being able to destroy any zombie regardless of stats. Compared to Squash, Lawnmower is a bit cheaper, but cannot target zombies on heights or aquatic lanes, so it cannot serve as a complete replacement for Squash.
It is best to play this when there are very few or no heights or aquatic lanes in the field, but this only applies on some plant missions; for competitive matches, it is advised to take control of the lanes where Lawnmower can't be played on.
Just to be safe, keep your most important zombies on the heights and aquatic lanes so that they are safe from Lawnmower, and if you are a Brainy hero, you can grant other zombies immunity with Parasol Zombie. Be careful against Chompzilla, however, as she can use moving cards such as Sweet Potato to move your valuable zombies to ground lanes where they can be easily destroyed by this trick.