Traditionalist was a secret achievement in Plants vs. Zombies Adventures. To achieve it, the player had to begin any level by planting a Sunflower. Traditionalist was very easy and could have been unlocked as soon as the player got the Sunflower.
The word "traditionalist" means someone who believes in and follows traditional ideas. Its name references the fact that frequently, a player will plant a Sunflower at the beginning of a level.