A while back (2 years ago) we had a disease and bug free rhody that was beautiful and fragrant, we took it to the fair and it got every bug known to man. It has taken until ow to get a viable plant but it has stll some problems. I am attaching a picture of some of the leaves and hope that someone can ID the problem. Insect, chemical or what. So here goes.
There are several possibilites for the spotted yellow color, ccjacko1910. (1) Some gardenia varieties (August Beauty, perhaps?) lose leaves in preparation for their first flush. The leaves could be slowly turning yellow and dropping off. (2a) You could also have an infestation by sucking insects, such as spider mites which feed primarily on the underside of the leaves. Tiny chlorotic dots or stipples appear on the upper leaf surface; tiny mites or eggs appear on the lower surface. I would check under the leaves (ck during the day first and if you notice nothing, also check during the evening, when most pests are visible). (2b) Similar in habit are small aphids, which cling to leaf undersides. (3) Finally, have you sprayed near the plant with chemicals that might have drifted onto the gardenia with the wind?
thanks for the assistance. I realized that for some unnown reason I called it a rhody when it is a gardenia and posted it in the container section of the forum. Am hoping that it is spider mites and have sprayed the plant top and bottom of the leaves with insecticidal soap. Will give it a second treatment in 2 weeks. Have sprayed the plant itself after the problem showed thinking aphids and other insects never thought of the spider mites.
I am going to post before and after pics on the container thread that I have going. I wish they had a forum for gardenias but don't know who to contact to start one. Once again thank you.