annual, perennial
aquatic, water
noxious (esp. AmE)

kill
clear, get rid of, pull up, remove
control, keep down, keep under control
Fill the bed with annual flowers to keep the weeds down.

grow, spread
spring up
There were weeds springing up through the gravel.

control
killer (usually weedkiller)
trimmer
growth
seed, seedling

Weed is used with these nouns as the object:
garden