We were at a rest stop on I-5 in California when I saw a sign across the parking lot: "Warning, Poison Oak". It being everyone's favorite three-leaved plant, I had to grab my camera and take a look. The leaves on some plants had already turned red for the fall, so I thought they made good subjects. I used macro focus, a small F-stop to enhance depth of field, and flash because it was shady. I didn't tamper with the red saturation at all.