| Common Name | Latin Name |
|---|---|
| Tall Fennel | see Dogfennel |
| Tall Fescue | Lolium arundinaceum |
| Tall Goldenrod | Solidago canadensis var. scabra |
| Tall Green Milkweed | Asclepias hirtella |
| Tall Morningglory | Ipomoea purpurea |
| Tall Oatgrass | see Bulbous Oatgrass |
| Tall Thistle | Cirsium altissimum |
| Tall Waterhemp | see Common Waterhemp |
| Tansy Mustard | Descurainia pinnata |
| Tansy Mustard | see Pinnate Tansymustard |
| Tearthumb | Polygonum arifolium |
| Teaweed | see Prickly Sida |
| Texas Panicum | Panicum texanum |
| Texas Thistle | see Buffalobur |
| Thorny Buryweed | see Spiny Cocklebur |
| Thoroughwort Pennycress | see Perfoliate Pennycress |
| Three-way Sedge | Dulichium arundinaceum |
| Timothy | Phleum pratense |
| Toothed Spurge | Euphorbia dentata |
| Toothed Spurge | see Wild Poinsettia |
| Touch-me-not | Impatiens capensis |
| Trailing Crownvetch | see Crownvetch |
| Tree-of-Heaven | Ailanthus altissima |
| Trifoliate Orange | Poncirus trifoliata |
| Tropic Croton | Croton glandulosus var. septentrionalis |
| Tropical Soda Apple | Solanum viarum |
| Trumpet Penstemon | Penstemon tubaeflorus |
| Trumpetcreeper | Campsis radicans |
| Tufted Knotweed | Polygonum caespitosum var .longisetum |
| Tumble Pigweed | Amaranthus albus |
| Tumbleweed | see Russian Thistle |
