There are. A lot of fanfic authors like to explore different sides of characters. In some 'Naruto likes gardening' fanfictions, Naruto might use gardening as a form of relaxation from his intense ninja training. It could also be a way for him to connect with nature, which is not something that's often focused on in the main series. So, it can add a really interesting and unique aspect to his character.
Sure. You might find that some fanfictions incorporate gardening into Naruto's character development. For example, he could learn patience and the value of nurturing through gardening, which are skills that also translate to his growth as a ninja. Additionally, the stories could involve Naruto sharing his love for gardening with his friends, like Sakura or Kakashi, and how they react to this new side of him.