The Gardener is a special monster that only appears in the subdungeon where The Earthmother is unlocked. Several Gardeners spawn among the plants, all at level 9. Due to the combination of Physical resist and Retaliate: Fireball, they are very difficult to fight, although effects such as Avatar's Codex, Really Big Sword, , or the Half-Dragon trait Trait: Dragon Breath Dragon Breath are just a few of the possible ways to work around their defenses.
However, there is no purpose in fighting them except as a self-imposed challenge, as they give No Experience and do not drop any rewards when killed. The player can simply walk around them, cutting a path through the plants, to reach the altar of The Earthmother.
Once The Earthmother has been unlocked, Gardeners no longer appear anywhere in the game.