Lyric discussion by graceMazin 

Cover art for Snail lyrics by Smashing Pumpkins, The

if you substitute flower with poppies (opium) suddenly the song makes sense...

Just to add - if you google around you'll find Billy was a functional user of opiate painkillers around this time (heroin was used but not frequently).

see here: http://en.allexperts.com/q/Smashing-Pumpkins-593/f/Billy.htm