|I bought five gallon gardenia plant from Amorstrong nursery in Irvine. But the label on the container showed that the plant was coming from Monrovia nursery. After a month or so, the flower buds start to turn brown at joint area and dropped. Also, the leaves turn yellow and some turn dark brown like has been burnt. This was the third time I tried to plant Gardenia without success. I used acid fertilizer, peat moss, blood iron, cotton seeds and iron pallet, nothing works. Please advise - what did I do wrong. Thanks|
|You didn't say if your gardenia is indoors in a pot or outside in the landscape, but considering your location I'm going to assume it's outdoors. There are many things that can cause leaf drop. One is common - gardenias are very susceptible to spider mites, which cause tiny webs on the undersides of leaves and where the leaves join the stems. Another way to detect them is to take a sheet of white paper out to the bush, tap a few branches on to the paper, fold the paper in half and press/rub together. If you see little red, blue, or brown smears, those are spider mites. You can spray them off with a strong blast from the hose (do this daily until they're under control). A product called Neem can also be used to treat for spider mites. Follow product instructions for application.
Gardenias need at least a half day of full sun to bloom, but at the same time, the hot afternoon sun can be tough on them. Morning sun is best, so an eastern location would be ideal. You might also try a southern or western exposure with some filtered shade. Buds that turn black or drop and bottom leaves that are yellowed are sure signs that gardenias aren't getting enough light.
Leaf drop can also be caused by improper soil pH (gardenia require 5 to 5.5pH - on the acid side.) Yellowing and leaf drop are also signs of various soil nutrient deficiencies such as nitrogen, zinc, and iron.
Finally, if the air is too dry, your plant will drop buds and leaves. Try sprinkling the plant every morning to increase humidity (and also discourage spider mites!).
Hope these suggestions help!