| Common Name | Latin Name |
|---|---|
| Water Hyacinth | Eichhornia crassipes |
| Water Pennywort | see Marsh Pennywort |
| Water Plantain | Alisma subcordatum |
| Water Purslane | Ludwigia palustris |
| Water Willow | Justicia americana |
| Water-starwort | Callitriche heterophylla |
| Waterhemp | see Common Waterhemp |
| Waterlilies | Nymphaea spp. |
| Watermeal | Wolffia spp. |
| Watershield | Brasenia schreberi |
| Waterthread Pondweed | see Variable-leaf Pondweed |
| Western Ironweed | see Baldwins Ironweed |
| Western Panic-grass | see Lindheimer's Panic-grass |
| Western Rock Jasmine | Androsace occidentalis |
| Western Salsify | see Goat's-beard |
| Western Tansymustard | see Pinnate Tansymustard |
| Western Yarrow | see Common Yarrow |
| Wheat | Triticum aestivum |
| White Avens | Geum canadense |
| White Campion | Silene alba |
| White Clover | Trifolium repens |
| White Flowered Mazus | Mazus japonicus |
| White Heath Aster | Aster pilosus |
| White Hickory | see Hickory |
| White Horehound | see Horehound |
| White Sage | Artemisia ludoviciana |
| White Sagebrush | see White Sage |
| White Sanicle | see White Snakeroot |
| White Snakeroot | Ageratina altissima |
| White Sweet Clover | Melilotus alba |
| White Vervain | Verbena urticifolia |
| White evening-primrose | see Showy Evening-primrose |
| White wand beardtongue | see Trumpet Penstemon |
| White wand penstemon | see Trumpet Penstemon |
| Wild Basil | Satureja vulgaris |
| Wild Bergamot | see Bee-balm |
| Wild Blue Phlox | see Blue Phlox |
| Wild Buckwheat | Polygonum convolvulus |
| Wild Carrot | Daucus carota |
| Wild Chervil | Chaerophyllum procumbens |
| Wild Chrysanthemum | see Mugwort |
| Wild Four-O Clock | Mirablis nyctaginea |
| Wild Garlic | Allium vineale |
| Wild Grapes | Vitis spp. |
| Wild Mustard | Brassica kaber |
| Wild Oat | Avena fatua |
| Wild Onion | Allium canadense |
| Wild Pansy | see Field Violet |
| Wild Parsnip | Pastinaca sativa |
| Wild Poinsettia | Euphorbia heterophylla |
| Wild Radish | Raphanus raphanistrum |
| Wild Sunflower | see Common Sunflower |
| Wild Sweet William | see Blue Phlox |
| Wild Vervain | see Blue Vervain |
| Wild-proso Millet | Panicum miliaceum |
| Winged Sumac | Rhus copallina |
| Wingstem | Verbesina alternifolia |
| Wire Grass | see Bermudagrass |
| Wireweed | see Prostrate Knotweed |
| Witchgrass | Panicum capillare |
| Woodland Phlox | see Blue Phlox |
| Woodrush | Luzula bulbosa |
| Woolly Croton | Croton capitatus |
| Woolly Cupgrass | Eriochloa villosa |
| Wooly Ragwort | Senecio tomentosus |
