Chao garden did not originate from fanon, and more information can be found on their respective wiki(s). You may read more about it on the following wiki(s):

Chao garden is the habitat for Chao. It has made appearances in Sonic Adventure and Sonic Adventure 2 and as a Tiny Chao garden in Sonic Advance, Sonic Advance 2 and Sonic Pinball Party.


Sonic Heroes 2

Sonic Heroes 2 has a Chao garden of its own. The Sonic Adventure gardens in Station Square, Mystic Ruins and the Egg Carrier are recycled and the Sonic Adventure 2 all-in-one lobby is located in Metropolis. The Metropolis branch is visited by Team Rose in their storyline and briefly in Team Chaotix' storyline. To unlock the Chao garden, the player needs to access it in either storyline.

Chao World Wii

Chao gardens appear in Chao World Wii as a place of inhabitance for the game's Chao. There are several different Chao Gardens to pick from; the three gardens from Sonic Adventure (Station Square, Mystic Ruins and the Egg Carrier) and the three gardens from Sonic Adventure 2 (Hero Garden, Neutral Garden and Dark Garden) are included, and so are the new gardens New Sega City Garden, Space Garden, Seaside Paradise Garden, Cave Garden, Green Hill Zone Garden and Mystical Garden.

Chao Island/Chao In Space

Chao gardens are set to appear in Chao Island and Chao In Space, however it is unknown which gardens make an appearance.