brew
bairn
Autumn. You lied about the b.
Bovine.
broccoli bamboo beans berries banana basil
Bacteria!
Bandit is a synonym for pirate. It begins with the letter b.
"Cabbage".
"Biology" is the word that starts with a B and is related to science and plants. It is the branch of science that studies living organisms, including plants.
The word you seek is botulism.
Could be bi-annuals, as opposed to annuals.
botany