I have tried growing gardenia trees for two years. I keep them on the back porch where they get afternoon indirect sun. My problem is the buds drop before opening and both got infested with a white insect that left webbing. I tried insect spray, but this did not help. Any suggestions?
The Gardener’s Answer
Hi, Mary in Kentucky: Gardenias are grown for their scented flowers. Here in Kentucky, we consider them a tropical since they will not tolerate our winter weather. They can certainly be brought inside to over-winter but they do tend to be a bit temperamental. They require very specific growing conditions and are happiest growing in nutrient-rich, acidic soil that is well-drained yet consistently moist. They prefer to grow in warm, humid environments and may benefit from shade during the hot afternoon when living outdoors. Indoors, they should be given as much light as possible. Bud drop, although frustrating, is not uncommon among gardenias. There is no one specific reason for bud drop but more likely a combination of inconsistent moisture levels and changes in temperature or location. In general, gardenias do not bloom well when the temperatures get really hot. Finding the right balance can be a challenge. Gardenias are susceptible to several different insects; from the webbing you described I suspect you have spider mites. They are not actually an insect so this would explain why your insect spray did not work. It is always a good idea to have the problem identified before treating any plant. Gardenias are sensitive to horticultural oils and soaps so identifying the problem is essential for control purposes. As with any product make sure the plant you are about to treat is listed as safe on the product label. When plants are stressed it is common for them to become infested with different insects. You can take a sample to your local garden center or Extension service for a diagnosis. For now, wiping the foliage with a wet cloth (especially on the underside) will help remove some of the insects/mites.