| Eupatorium hymenolepis B.L. Rob., 1907 |
| Eupatorium hypomalacum B.L. Rob., 1903 |
| Eupatorium hyssopinum A. Gray, 1880 |
| Eupatorium iltisii (R.M. King & H. Rob.) Whittem. ex B.L. Turner, 1997 |
| Eupatorium imitans B.L. Rob., 1923 |
| Eupatorium incarnatum Walter, 1788 |
| Eupatorium incomptum DC., 1836 |
| Eupatorium innumerosum DC., 1836 |
| Eupatorium irrasum (B.L. Rob.) H. Rob., 1925 |
| Eupatorium isolepis B.L. Rob., 1907 |
| Eupatorium ivifolium L., 1759 |
| Eupatorium jejunum Standl. & Steyerm., 1944 |
| Eupatorium karwinskianum A. DC., 1836 |
| Eupatorium koelliifolium Greene, 1896 |
| Eupatorium laevigatum Lam., 1788 |
| Eupatorium lanicaule B.L. Rob., 1900 |
| Eupatorium lasioneuron Hook. & Arn., 1838 |
| Eupatorium lasium B.L. Rob., 1923 |
| Eupatorium leiophyllum Less., 1831 |
| Eupatorium lemmonii B.L. Rob., 1892 |