I have 2 house plant gardenias that I put out in full sun on my patio beginning in late April or early May. They have been doing extraordinarily well this year until this past Saturday. Last Saturday evening both were fine but on Sunday morning the gardenia on the left in the picture "Both Gardenias Together" showed that at least half of its leaves were turning brown. The plant on the right has a leaf or three with the same kind of damage but otherwise still looks perfectly healthy. The second picture is a closeup of the damaged gardenia and the third picture shows a stem where the leaves on the right show the top of the leaves and the leaves on the left of the stem show the underside. The damaged gardenia still has its newest growth at the stem tips looking bright green and healthy and the same with the leaves deeper inside the plant also looking healthy. My first thought is that I must have forgotten to water the plant on the left and it has been so hot that one day in the sun could cause sunburn. The damaged leaves are quickly falling off. For now, I've moved both plants into the shade. Any ideas? Thank you,