Origin of "full blown?"

Can anybody help me understand the origin of the phrase "full blown?" I read it most often in conjuction with HIV/full-blown AIDS. Just curious as to where the phrase originated.

It's from blooming. One meaning of "blow" is "to blossom." A full-blown flower is one whose petals have opened as far as they'll go.

There's a more unpleasant association with maggots. When flies are attracted to meat and lay their eggs on it, the meat is said to be 'blown' or 'fly blown'. After a few days the eggs hatch and small maggots can be seen feeding on the meat.