For my first mod I kept it simple and added back both the Pocket Addition Blue Rose and the Console Addition Red Rose. They seem to work the same way as regular flowers except they spawn in flat worlds which I didn't know how to fix. Also I had to recreate both textures in photoshop because I could not make them look right in the mcreator texture maker so sorry if there is any mistakes. I'm sure this mod has been made before so sorry if I made this mod after you made yours.
Latest supported Minecraft version