| Good King Henry | CHENOPODIUM BONUS HENRICUS |
| Gorse # | ULEX EUROPAEUS |
| Great Bindweed | CALYSTEGIA SYLVATICA |
| Great Burdock | ARCTIUM LAPPA |
| Gooseberry | RIBES UVA-CRISPA |
| Grass-of-Parnassus | PARNASSIA PALUSTRIS |
| Great Mullein | VERBASCUM THAPSUS |
| Greater Birds-foot Trefoil | LOTUS ULIGINOSUS |
| Greater Plantain | PLANTAGO MAJOR |
| Greater Stitchwort | STELLARIA HOLOSTEA |
| Green Alkanet | PENTAGLOTTIS SEMPERVIRENS |
| Ground ivy | GLECHOMA HEDERACEA |
| Groundsel | SENECIO VULGARIS |
| Guelder Rose | VIBURNUM OPULUS |
| Hawthorn | CRATAEGUS MONOGYNA |
| Hazel | CORULUS AVELLANA |
| Hedge woundwort | STACHYS SYLVATICA |
| Hellebore, Green | HELLEBORUS VIRIDIS |
| Hellebore, Stinking | HELLEBORUS FOETIDUS |
| Herb Robert | GERANIUM ROBERTIANUM |
| Hogweed | HERACLEUM SPHONDYLIUM |
| Honeysuckle | LONICERA PERICLYMENUM |
| Hop | HUMULUS LUPULUS |
| Hornbeam | CARPINUS BETULUS |
| Horse-radish | ARMORACIA RUSTICANS |
| Horseshoe Vetch | HIPPOCREPIS COMOSA |