This species belongs to Hillia subg. Hillia, and is apparently pollinated by hawkmoths. It has the largest flowers of the genus, which are quite showy. As with many nocturnally flowering species there is notable variation in corolla size within this species. It has been rather sporadically collected. Hillia macromeris is similar to Hillia macrophylla and these are found in the same general region; Hillia macrophylla is much more commonly collected.