Don't hold your breath. If anything, that could be an add-on mod. Dye Depot does a very sketchy thing internally, so establishing compatibility with it at all will likely be an annoying thing already.
There is currently no plan to expand the range of colors in Botania, as the bonus of doing so currently is limited to the presence of a single mod, and doesn't really add much, other than "being cool", for a lot of work. Keep in mind we would need to design new flower textures for each added color.