Wow, thanks for the great feedback, guys!
I honestly have no idea what you are talking about when you say geotextiles. As for irrigation, no, there is no irrigation in these rock beds. However, they are on a grade and would run off onto a (kind of) grassy area below, and then into a drainage reservoir. I didn't consider runoff as it doesn't rain much here, but then again we got about 4" in the past week! And the last thing I need is the TCEQ all over me about contamination into the reservoir.
I will definitely look into the other products you mentioned. I was hoping to not have to reapply so often, but if that's what we gotta do, that's what we gotta do.
What if the hokey pokey really IS what it's all about?!