I'm not sure what the hell oldsanclem just said, so perhaps I can muddle through and reiterate his key points:

When gathering your trimmings, place them in a bag that contains nothing other than your trimmings.

When trash day comes, put your bag of trimmings in the trash can right before the trash man gets there. This eliminates the possibility of the cops doing a "trash pull", which they can do without a warrant.

If you cannot do this, then here are a few more options:
-Compost it
-take a handful of the stems and break them into small pieces. Then, go to a public trash can which is not covered by surveillance camers and dump it in there. Don't use the same trash can twice in between trash pickups.
-Put them in a blender and make a *very* fine powder out of them and flush them down the toilet. Make sure they are chopped very fine unless your plumber is "cool".
-Eat them (ewww)
-Smoke them (again, ewww!)

Good luck!