Gardenias let you know when they are unhappy. It looks as though fella isn’t feeling well. To begin with, I suspect the leaves began to turn yellow and fall off. Bugs. Probably scale on the underside of the leaves. Spray the entire plant, especially the stems and trunk, with two applications of any product listed for controlling scale insects: Sevin, malathion, Safer’s soap. Next apply a systemic insecticide containing Imidachloprid. Follow the directions carefully. It is a systemic insecticide and will be absorbed by the roots and will deter future bugs from the inside out. You will need to do this every six months. Next and very important add two cups of fertilizer designed for gardenias, azaleas, camellias to the mulched area and water well. That’s it. You should notice a change in 30-45 days. You may have to trim any dead branches back to until you see green tissue when you cut. That’s it. Let us know how things work out.
About the Author: Garden Answers
My grandmas had three big huge gardenias in front of porch I loved them but I can’t keep mine going I bought a two ft one not suppose to get much taller it was looking beautiful now leaves turning yellow & brown dying live in central Texas have had extensive high heat all summer plant been outside whole time like said was looking beautiful till last month or so