Lost,
Yep, you pretty much nailed it.
The story: One evening in summer we heard what sounded like gunshots down the street. Not firecrackers but the distinct sound of pistols. We called 911 as there were weird things going on down there before.
A few minutes later, my son comes running down from upstairs saying he had seen someone in our backyard. I grabbed a weapon and Shaun grabbed his 30.06 and when I saw the guy, I calmly suggested he start eating dirt while laying on his stomach. (It was an area of the yard where I had a swimming pool but had not finished filling in and turning into a garden.) Called 911 again and brought the guy to the side of the house where we had plenty of light. About 10 minutes later (this is now around 1 am) the cops finally showed up, questioned the guy and some friends who stopped by, then let him go.
I went to bed but at about 3:00 am the guy shows back up and asks my wife and son if it is OK to search the yard, that he lost his cell phone. They watched him search but he couldn't find it. Not sure why no one tried to dial the number - apparently they aren't as logical as me.
That fall and the following spring I filled in the area, tilled it and sowed seeds or added plants. I noticed all these weeds that looked like pot and presumed it was some look-alike plant. Just cut them out with a hoe. The next year, there were some more, though not as many. I let a couple grow until they had a few leaves, plucked them, let them dry and then burnt them. Yep, one cannot mistake the smell of a particular herb that Iggy likes.
Last year, I saw a couple that I removed but apparently missed a couple of others. They grew around potatoes and tomatoes and got about two feet tall until I noticed them.
What's scary is that I stopped a group of people who belong to the Citizens on Patrol Program, residents who are trained to be the eyes and ears of the police department. A couple of them had read about my gardening and wanted to see it. I can only imagine if they had found pot plants them believing the story I've just posted!
My presumption is the guy lost a bag of seeds and over time, with tilling the garden both east/west and north/south I managed to spread them around, or the bag or sack they were in came open and they got scattered.
If any come up this year I'll take pictures (but not post them for a few days - until they are buried in with grass clippings and such!). Otherwise, I can see Iggy taking a road trip south.
Mike