Just dig around in the minecraft_version.jar for a bit, you'll find where everything is. Foliage and some other stuff like water is usually monochrome so that biomes can individually color them.
Getting into tge Minecraft jar is easy. You only need a valid Minecraft Java account. Then locate the jar inside of the versions folder. Then, if your zip program is good enough, just peek inside. If it isn't good enough, rename .jar to .zip. It will tell you that that can corrupt the data, but it won't. Then unzip if you have to. There will be all of Minecraft's folders in there. Including a ton of .class files. Unless you are modding Minecraft the very, very hard way, those can be deleted.