H – H
| Helianthus annuus | Common sunflower |
| Helichrysum arenarium | Dwarf everlast |
| Helichrysum italicum | Curry plant, Licorice plant |
| Helleborus dumetorum | Hellebore |
| Helleborus niger | Black hellebore |
| Hepatica triloba (H. officinalis) | Liverleaf |
| Herniaria glabra | Smooth rupturewort |
| Herniaria hirsuta | Hairy rupturewort |
| Hierochloe odorata | Sweetgrass |
| Hippophae rhamnoides | Sea buckthorn |
| Humulus lupulus | Hops |
| Hyoscyamus niger | Henbane |
| Hypericum perforatum | St John’s wort |
| Hyssopus officinalis | Hyssop |