The comet bloom wasn't pickable until I started the missing person job
Saved my game at that point and tried to get it to respawn but it failed to do so when I entered and left either the ghost hideout or the wasted garage exit.
I reloaded my save, left the comet bloom alone, and completed the missing person job.
Entering and leaving the ghost hideout still didn't work, but entering and leaving the wasted garage exit did finally cause the bloom to respawn
EDIT: Stops working until the comit respawns later on in the game if you don't leave a comet behind when your finished for the time being...