Plants
From PinataIsland.info, the Viva Piñata wiki
Your choice of plants will determine which of the piñata species are attracted to your garden, since they all have individual requirements. Planting flowers and trees, and growing vegetables all affect which of the unique piñatas you will see. Your reward for creating an appealing paradise is to watch the piñatas visit and eventually reside there, which is when the fun really starts.
Plant life is what you put in your garden, like trees and flowers and bushes and, well you get the idea. Plant life comes in many forms, like daisies or tulips.
So now put tons of plant life in your garden? Mmmm'kay?