Using a color associated with the intention (instead of a general color for manifestation) is what I prefer to do 
Additionally, if you don’t have a specific color candle, you could always incorporate the energy of that color in other ways - like using a colored crystal, a flower of that color, even a candle holder or altar cloth of the color you’d like. Another option could be to dress a white candle, imbuing it with energy and intention of the herbs in the oil you dress it with 
Lots of options available to you, @LunarEssence! However you decide to proceed, I’m wishing you happy and blessed spellwork 
