Two months ago I bought two flowering healthy looking gardenias whose leaves are now turning black at the tips & edges & fall off at the lightest touch. They stopped flowering & have created only one new bud that fell off before opening. I live in Egypt & it's hot & dry, so I water & mist the plants often. Maybe too often? On the soil I have found teeny tiny silver bugs. I read gardenias are hard to keep. What can I do to turn things around?
Gardenias grow best in warm (but not hot) conditions with high humidity. Misting is at best a very temporary way to raise the humidity. If you place other plants around the gardenia or use a pebble tray filled with water (which will evaporate and raise the humidity in the area) you may have better luck at preventing the black leaves and leaf loss.