Several different plants are superficially quite similar to the white wood aster, but close examination as well as knowledge of the plants' differing habitats and ranges can readily distinguish them. The most similar species is the mountain wood aster ("Eurybia chlorolepis"), which was previously considered conspecfic with "E. divaricata". "E. chlorolepis" differs in having flower stalks that are longer than 1.5 cm, while those of "E. divaricata" are shorter than this. The involucres of the mountain wood aster are generally between 6.5 and 9 mm in length, while those of the white wood aster are normally from 4.2 to 6.5 mm long, but in rare cases they may be as long as 7.5 mm. The mountain wood aster almost always has more rays than the white wood aster: the former usually has 12 to 16, but occasionally as few as 10, while the latter generally has 5 to 10 and never more than 12. The rays are also longer on the mountain wood aster at 17 to 18 mm in most cases, while the white wood aster's are generally only 10 to 15 mm. Lastly, "E. chlorolepsis" is present only from southern Virginia south to Georgia in the Appalachian Mountains at altitudes of , while "E. divaricata" can be found from southern Canada south to Alabama, meaning their ranges only overlap in the southern United States, and there only at high elevations.