During character creation, a plant type must be chosen. There are 3 plant types: Cactus, Tree, and Flower. Your bonus is determined by your level. At level 20, you will begin to see a bonus. Plants gain 1 bonus for every 200 levels each time they train their bonus attribute. Plant type can be changed in the settings menu for $100,000.
Cactus: Cactus are offensive plants. Their bonus attribute is potency.
Tree: Trees are defensive plants. Their bonus attribute is girth.
Flower: Flowers are speedy plants. Their bonus attribute is responsiveness.