| Common Name | Latin Name |
|---|---|
| Bachelors Buttons | see Cornflower |
| Baldwins Ironweed | Vernonia baldwinii |
| Balloonvine | Cardiospermum halicacabum |
| Barnyardgrass | Echinochloa crus-galli |
| Basketgrass | see Japanese Stiltgrass |
| Bathurst Bur | see Spiny Cocklebur |
| Beaked Nightshade | see Buffalobur |
| Bear's Foot | see Yellow-flowered Leaf-cup |
| Bear-grass | see Yucca |
| Bearded Sprangletop | Leptochloa fusca ssp. fascicularis |
| Bedstraw | Galium aparine |
| Bee-balm | Monarda fistulosa |
| Beef-steak Plant | see Perilla Mint |
| Benghal Dayflower | Commelina benghalensis |
| Bermudagrass | Cynodon dactylon |
| Bigroot Morningglory | Ipomoea pandurata |
| Birds Foot Violet | Viola pedata |
| Birdsfoot Trefoil | Lotus corniculatus |
| Bitter Sneezeweed | Helenium amarum |
| Bittersweet Nightshade | Solanum dulcamara |
| Black Locust | Robinia pseudoacacia |
| Black Medic | Medicago lupulina |
| Black Oak | Quercus velutina |
| Blackjack Oak | Quercus marilandica |
| Blackseed Plantain | Plantago rugelii |
| Bladder Campion | Silene vulgaris |
| Bladderworts | Utricularia spp. |
| Bloodroot | Sanguinaria canadensis |
| Bloom Fell | see Birdsfoot Trefoil |
| Blue Phlox | Phlox divaricata |
| Blue Vervain | Verbena hastata |
| Blue-Bottles | see Starch Grapehyacinth |
| Bluebell | see Virginia Bluebells |
| Blueweed | see Viper's Bugloss |
| Bouncing-bet | Saponaria officinalis |
| Brazilian Elodea | Egeria densa |
| Brazilian Waterweed | see Brazilian Elodea |
| Bristly Cattail Sedge | see Frank's Sedge |
| Bristly Greenbrier | Smilax hispida |
| Brittle Naiad | see Slender Naiad |
| Brittleleaf | see Slender Naiad |
| Broadleaf Arrowhead | see Midwestern Arrowhead |
| Broadleaf Dock | Rumex obtusifolius |
| Broadleaf Pepperweed | see Perennial Pepperweed |
| Broadleaf Plantain | Plantago major |
| Broadleaf Signalgrass | Brachiaria platyphylla |
| Broomsedge | Andropogon virginicus |
| Brown Mustard | see Indian Mustard |
| Browntop Millet | Brachiaria ramosa |
| Buckbrush | Symphoricarpos orbiculatus |
| Buckhorn Plantain | Plantago lanceolata |
| Buffalobur | Solanum rostratum |
| Bugleweed | Ajuga reptans |
| Bulbous Buttercup | Ranunculus bulbosus |
| Bulbous Oatgrass | Arrhenatherum elatius var. bulbosa |
| Bulbous Tall Oatgrass | see Bulbous Oatgrass |
| Bull Thistle | Cirsium vulgare |
| Bullbrier | see Greenbrier |
| Burcucumber | Sicyos angulatus |
| Bush Honeysuckle | Lonicera maackii |
| Bushy Wallflower | Erysimum repandum |
| Butterfly Milkweed | Asclepias tuberosa |
| Butterflyweed | see Butterfly Milkweed |
| Butterweed | see Cressleaf Groundsel |
