|The 7 Kleim's Hardy Gardenias I planted last spring (2000) are all showing the same symptoms and problems this year as they did last year, only worse. They bloomed most of last summer but experienced the following problems:
-yellow leaves (the leaves are either all yellow or a healthy green)
-leaf drop by the yellow leaves
-dying branches and thinning of the plant
-a general thin and weak appearance (not lush and flush with new growth)
-surviving growth is on the upper part of branches, not full from inside
This spring there are no buds or blooms and the yellowing is back. I only water the plants when we receive no rain for extended periods of time. The plants were planted in mostly clay soil but I did dig reasonably large holes and amended the soil with a pre-packaged mixture of bark, peat moss, and compost/manure designed for acid loving plants. I also recently gave them iron although I don't think a lack of iron is the problem. Any thoughts or advice would be greatly appreciated.
|Gardenias aren't doing well. They are very particular about growing conditions, and I'll bet the soil conditions are not to their liking, even though you have worked hard to provide the right conditions. Often when we dig a hole in clay soil and fill it with the "right stuff", water will collect in the good soil as it drains from the clay. Even though gardenias are moisture-loving, without a balance of air and moisture in the soil, roots can rot. Perhaps if you make raised beds using the acid-loving plant mixture and transplant the gardenias into them, the plants will revive.
Another possibility is that they aren't getting enough moisture. Trees and shrubs need regular moisture during their first season so they can stay healthy while they develop a strong root system. Once established, the soil should be kept evenly moist.
For gardenias, yellowing can result from a) root problems (too dry or too wet), b) pest problems such as whitefly, scale, or mites, or c) a lack of iron. Even if you provide iron, if the soil pH is too alkaline, the plant can't take up the iron it needs because it won't be in an absorbable form. It may well be that the acidic soil you used to fill the holes has been neutralized by calcium in the surrounding soil. Check the soil pH using a home test kit (they're a few dollars and can be found at garden centers) or call your county agricultural extension office to arrange a soil test. I hope this helps you get your gardenias back in shape!