| Common Name | Latin Name |
|---|---|
| Hairy Bittercress | Cardamine hirsuta |
| Hairy Galinsoga | Galinsoga ciliata |
| Hare'S-Foot Clover | see Rabbitfoot Clover |
| Healall | Prunella vulgaris |
| Hedge | see Osage Orange |
| Hedge Bindweed | Calystegia sepium |
| Hedge Mustard | Sisymbrium officinale |
| Hemp Dogbane | Apocynum cannabinum |
| Hemp Sesbania | Sesbania exaltata |
| Henbit | Lamium amplexicaule |
| Herb Of Grace | see Blue Vervain |
| Hickory | Carya tomentosa |
| Highbush Blackberry | Rubus argutus |
| Hoary Plantain | Plantago virginica |
| Hoary Puccoon | Lithospermum canescens |
| Hogwort | see Woolly Croton |
| Honey Locust | Gleditsia triacanthos |
| Honeyvine Milkweed | Ampelamus albidus |
| Hop O'My Thumb | see Birdsfoot Trefoil |
| Hop Sedge | Carex lupulina |
| Hop Trefoil | see Large Hop Clover |
| Hophornbeam Copperleaf | Acalypha ostryifolia |
| Horehound | Marrubium vulgare |
| Hornwort | see Coontail |
| Horsenettle | Solanum carolinense |
| Horsetail | see Field Horsetail |
| Horseweed | Conyza canadensis |
| Hush-tomatoe | see Smooth Groundcherry |
