Wanting to determine the Five Elements attributes of each type of medicinal herb is not a task that can be done in a short moment, or even completed in a few years. Instead, it requires a gradual process of exploration over an incredibly long period of time to eventually succeed.
As for why herbs that should be of wood attributes have the issue of Five Elements attributes, Zhang Xiaohua vaguely has some ideas. For instance, the Flaming Red Grass turns red, and the surroundings where it grows are devoid of plants and grasses, to the point that even the soil turns into stone. It is undoubtedly fire attributed. The two main ingredients of the Crimson Flame Pill, the Crimson Pearl Grass, and the fire-attributed Flaming Red Grass, complement each other perfectly, so the former must be water attributed.
Of course, many other herbs cannot have their Five Elements attributes determined directly from their appearance.
