| English Name | Scientific Name | Spanish Name |
| Garlic | Allium sativum | Ajo |
| Garlic Mustard | Alliaria officinalis | Aliaria, Hierba del ajo |
| Gas Plant, Burning Bush | Dictamnus albus | Dictamo blanco |
| Gayfeather, Blazing Star | Liatris punctata | Cachana |
| Gentian | — Gentiana lutea G. kochiana |
— Genciana, G. amarilla, G. mayor, Gengiba, Quina de pobre, Unciana, Xaranzana Genciana de koch |
| Geranium | Pelargonium spp | Geranio, Malvón |
| Germander, Wood Sage | — Teucrium chamaedrys T. scardonia |
— Camedrio, Encinilla, Germandrina, Hierba tercianera, Pata de gallo, Sanguinaria Escordia |
| Giant Clover, Mexican Contrayerba, Scurf-pea | — Psoralea spp P. pentaphylla |
— Contrayerba blanco Contrahierba |
| Giant Hyssop, Fortune | — Agastache [Brittonastrum] aurantiacum A. mexicana or Cedronella mexicana Brittonastrum micranthum, B. pringlei |
— Unichi Abejera, Cidronela, Melisa, Noriten, Polvo del cerro, Tama, Toronjil, T. rojo, T. morado, T. blanco, T. de casa, T. de monte, Toroji, Toronjillo, Té de menta |
| Giant Reed | Arundo donax | Caña, C. de castilla, C. de hueca, Cañavera, Canuto, Carricillo, Carrizo, C. de la selva |
| Ginger | Zingiber officinalis / officinale | Ajengibre, Ajenijibre, Gengibre, Jengibre, J. dulce |
| Ginkgo Biloba | Ginkgo biloba | Ginkgo |
| Ginseng | — Panax quinquefolia P. ginseng |
— Ginseng Ginseng |
| Globeflower | Troillus europaeus | Calerones |
| Goats Rue | Galega officinalis | Galega |
| Golden Chamomile | Chrysanthellum indicum | Crisantelo |
| Goldenseal | Hydrastis canadensis | Cúrcuma canadiense, Hidrastis, Sello de oro |
| Goldenrod | Solidago spp | Vara de oro |
| Gooseberry | Ribes uva-crispa | Agraz, Arganzón, Cambronera colorada, Cambronera mata, Chincarros, Escambrones, Grosellero espinoso, Limoncillo, Uva crespa, U. espina |
| Gotu Kola, Water Pennywort | — Hydrocotyle asiatica H. ranunculoides |
— Centella asiática, Gotu Kola, Hidrocotile Ombligo de puerco |
| Grape Hyacinth | Muscari comosum | Muscarino |
| Grape Vine | Vitis vinifera | Vid |
| Grapefruit | Citrus x paradisi | Toronja |
| Green Gentian, Indiana Caustic Barley | Swertia radiata | Cebadilla |
| Gromwell Shrubby Gromwell Common Gromwell |
— Lithodora fruticosa Lithospermum officinale |
—
|
| Ground Ivy | Glechoma hederacea | Hiedra terrestre |
| Guaco, Hempweed | — Mikania guaco M. houstonis |
— Guaco Corazon de jesus, Guaco |
| Guarana, Paullinia, Brazilian Cocoa | —
Paullinia cupana |
—
Guaraná |
| Guava, Guayaba | — Psidium guajava P. sartorianum |
— Arazá, Arrayán, Guayaba, G. blanca, G. criolla, G. de algodón, G. pirulera, G. roja, G. tlahuanca, Guayabera, Guayabilla, Hurapo, Luma, Parcha, Piche, Sahuinto Arrayán, Guayabillo |
| Guazuma Tree, Pricklenut, West Indian Mulberry | —
Guazuma spp G. tomentosa |
—
Cuaholote, Guázima, Guasima, Huasima |
| Gum Weed | — Grindelia phanactis G. robusta |
— Pegapega, Tripa de juda, Yerba del buey Grindelia |
| Gumhead | Gymnosperma glutinosum | Escobilla, Jarilla, Pegajosa, Tatalencho |
| Gurmar Leaf, Gurmarbooti | Gymnema sylvestre | Gymnema |
