*buzz*

Cannabis plants do give off a different heat signal than other plants. Granted, outdoor grows aren't found via infared as much as indoor grows, but it is done, and it is a danger for lare scale grows. But if you're only growing a few plants, if you space them out nicely, I wouldn't worry about it.

And word from the growers is that cedar trees give off a similar heat signal, and those can be used as protection from choppers. I think it's cedar trees, anyway. :P