Bu
- Buchnera
- N Buchnera americana — bluehearts Endangered
- Buddleja
- X Buddleja davidii — butterfly bush, orange-eye, summer lilac
- Buglossoides
- X Buglossoides arvensis — corn gromwell, bastard alkanet
- Bulbostylis
- N Bulbostylis capillaris
- Bupleurum
- X Bupleurum rotundifolium — roundleaf thorowax
- Butomus
- X Butomus umbellatus — flowering rush
Read more about this topic: List Of Canadian Plants By Genus B