|What is the cause of the edges of the leaves on the upper branches|
of the Mystery Gardenia turn Rust colored. It has gone through the summer O.K but now it looks sad.
|What you describe is probably weather related. It's not too unusual for gardenia leaves to take on a reddish cast on the upper surfaces, and around the edges, especially on the most exposed leaves. This is generally weather-related, often because of cool nighttime temperatures or a result of hot summer sun. These leaves will eventually drop and be replaced with healthy new leaves.|
Best wishes with your garden!