| Ageratina tetragona (Schrad.) R.M. King & H. Rob., 1970 |
| Ageratina textitlana B.L. Turner, 2008 |
| Ageratina thomasii R.M. King & H. Rob., 1990 |
| Ageratina thyrsiflora (Greene) R.M. King & H. Rob., 1970 |
| Ageratina tomentella (Schrad.) R.M. King & H. Rob., 1970 |
| Ageratina trapezoides (Kunth) R.M. King & H. Rob., 1972 |
| Ageratina triangulata (DC.) B.L. Turner, 1987 |
| Ageratina triniona (McVaugh) R.M. King & H. Rob., 1972 |
| Ageratina venulosa (A. Gray) R.M. King & H. Rob., 1970 |
| Ageratina vernalis (Vatke & Kurtz) R.M. King & H. Rob., 1970 |
| Ageratina vernicosa (Sch. Bip. ex Greenm.) R.M. King & H. Rob., 1970 |
| Ageratina viburnoides (DC.) R.M. King & H. Rob., 1970 |
| Ageratina viejoana B.L. Turner, 1993 |
| Ageratina villarrealii B.L. Turner, 2010 |
| Ageratina viscosissima (Rolfe) R.M. King & H. Rob., 1981 |
| Ageratina warnockii B.L. Turner, 1987 |
| Ageratina wrightii (A. Gray) R.M. King & H. Rob., 1970 |
| Ageratina xanthochlora (B.L. Rob.) R.M. King & H. Rob., 1970 |
| Ageratina yaharana B.L. Turner, 2008 |
| Ageratina yecorana B.L. Turner, 1987 |