Annual bluegrass – Butterfly bush
- Weeds: Annual bluegrass – Poa annua
- Weeds: Barnyardgrass – Echinochloa crus-galli
- Weeds: Bentgrass, creeping – Agrostis stolonifera
- Weeds: Bermudagrass – Cynodon dactylon
- Weeds: Birdfoot Trefoil – Lotus corniculatus
- Weeds: Bittercress (Shotweed, Hairy bittercress) – Cardamine hirsuta
- Weeds: Bittersweet nightshade (European bittersweet) – Solanum dulcamara
- Weeds: Black medic – Medicago lupulina
- Weeds: Blackberry (Himalayan, Evergreen, Pacific) – Rubus spp.
- Weeds: Blue mustard (Purple mustard, Tenella mustard) – Chorispora tenella
- Weeds: Brackenfern, western – Pteridium aquilinum
- Weeds: Buffalobur – Solanum rostratum
- Weeds: Bull thistle – Cirsium vulgare
- Weeds: Buttercup, creeping – Ranunculus repens
- Weeds: Butterfly bush – Buddleja davidii