Alternative spellings of willowherb include willow-herb and willow herb.
Alpine Willowherb, Pimpernel Willowherb: Epilobium anagallidifolium (Synonym: Epilobium alpinum var. alpinum) -
Tall Annual Willowherb, Autumn Willowherb: Epilobium brachycarpum (Synonyms: Epilobium jucundum, Epilobium paniculatum, Epilobium paniculatum var. hammondii, Epilobium paniculatum var. jucundum, Epilobium paniculatum var. laevicaule, Epilobium paniculatum var. paniculatum, Epilobium paniculatum var. subulatum, Epilobium paniculatum var. tracyi) -
Smooth Spikeprimrose, Smooth Spike-primrose, Smooth Willowherb: Epilobium campestre (Synonyms: Boisduvalia glabella, Epilobium pygmaeum) - Annual.
California Fuschia, California fire Chalice, Zauschneria: Epilobium canum ssp. latifolium (formerly Zauschneria latifolia) -
Ciliate Willowherb, Common Willowherb, Purple-leaved Willowherb: Epilobium ciliatum ssp. ciliatum (Synonyms: Epilobium adenocaulon var. adenocaulon, Epilobium adenocaulon var. perplexans, Epilobium brevistylum, Epilobium brevistylum var. brevistylum, Epilobium brevistylum var. ursinum, Epilobium californicum, Epilobium ciliatum var. ciliatum, Epilobium glandulosum, Epilobium glandulosum var. macounii, Epilobium occidentale, Epilobium watsonii var. occidentale, Epilobium watsonii var. parishii) -
Ciliate Willowherb, Common Willowherb: Epilobium ciliatum ssp. glandulosum (Synonyms: Epilobium adnocaulon var. cinerascens, Epilboium adenocaulon var. occidentale, Epilobium brevistylum var. brevistylum, Epilobium ciliatum var. glandulosum, Epilobium glandulosum, Epilobium glandulosum var. glandulosum, Epilobium glandulosum var. occidentale, Epilobium watsonii var. occidentale) -
Fringed Willowherb, Pacific Willowherb, Watson's Willowherb, Watson's Willow-herb: Epilobium ciliatum ssp. watsonii (Synonyms: Epilobium franciscanum, Epilobium watsonii, Epilobium watsonii var. franciscanum, Epilobium watsonii var. watsonii) -
Club-fruited Willowherb, Club-pod Willow-herb, Talus Willowherb: Epilobium clavatum (Synonyms: Epilobium alpinum, Epilobium alpinum var. albiflorum, Epilobium alpinum var. clavatum, Epilobium clavatum var. glareosum, Epilobium glareosum) -
Dense-flower Willowherb, Denseflower Spike Primrose, Dense Spike-primrose: Epilobium densiflorum (Synonyms: Boisduvalia densiflora, Boisduvalia densiflora var. densiflora, Boisduvalia densiflora var. pallescens, Boisduvalia densiflora var. salina) - Annual.
California Willowherb, Suksdorf's Willowherb: Epilobium foliosum (Synonym: Epilobium minutum var. foliosum) -
Glaucus Willowherb, Smooth Willowherb: Epilobium glaberrimum ssp. fastigiatum (Synonym: Epilobium glaberrimum var. fastigiatum) -
Smooth Willowweed, Glaucus Willowherb: Epilobium glaberrimum ssp. glaberrimum (Synonym: Epilobium glaberrimum var. glaberrimum) - Herbage usually glaucous. Plants of drier, gravelly or rocky slopes, road cuts, etc. Leaves lanceolate to narrowly ovate, 25-45 mm long, widely spaced or barely overlapping. Stems 25-45 cm high. Ovaries hairy.
Sierra Willowherb, Hall's Willowherb: Epilobium hallianum (Synonyms: Epilobium brevistylum, Epilobium brevistylum var. subfalcatum, Epilobium glandulosum, Epilobium glandulosum var. tenue, Epilobium ursinum, Epilobium halleanum, Epilobium brevistylum var. tenue, Epilobium delicatum, Epilobium pringleanum) -
Hornemann's Willowherb, Alpine Willowherb: Epilobium hornemannii ssp. hornemannii (Synonyms: Epilobium alpinum, Epilobium alpinum var. nutans, Epilobium hornemannii var. hornemannii) -
Milk-flower Willowherb, White-flower Willowherb, White-flowered Willowherb: Epilobium lactiflorum (Synonyms: Epilobium alpinum, Epilobium alpinum var. lactiflorum, Epilobium hornemannii var. lactiflorum) -
Low Willowherb: Epilobium leptocarpum -
Bog Willowherb: Epilobium leptophyllum (Synonym: Epilobium palustre var. gracile) -
Yellow Willowherb: Epilobium luteum -
Small-flowered Willowherb, Small-flowered Willow-herb, Chaparral Willowherb: Epilobium minutum (Synonym: Epilobium minutum var. minutum) -
Slimstem Willowherb: Epilobium oregonense (Synonyms: Epilobium alpinum, Epilobium alpinum var. gracillimum) -
Pale Boisduvalia: Epilobium pallidum (Synonyms: Boisduvalia macrantha, Boisduvalia pallida) - Annual.
Swamp Willowherb, Marsh Willowherb, Wickup: Epilobium palustre -
Siskiyou Willow Herb: Epilobium siskiyouense -
Stiff Spikeprimrose, Torrey's Willowherb, Torrey's Epilobium, Brook Willowherb: Epilobium torreyi (Synonym: Boisduvalia stricta) - Annual.