Cultivated virtual plant ecosystems modeling by means of simple memoryless procedural agents is presented. The ecosystem growth is a dynamic process with a tendency to chaos. An agent can move in the ecosystem and perform certain actions defined by users in the agent description file. Agents can seed new plants, pull out weeds, water plants, and communicate by message passing to distribute their tasks. An example of a successive garden cultivation in a wild ecosystem is presented. Agents first eliminate weeds, prepare space for and lay sidewalks, plant garden flowers, and protect their development. The main contribution of this paper is to show that autonomous agents can be used as a tool for user assisted procedural modeling of highly complex scenes.