|I have a patio gardena tree and leave contine to fall and turn black. I have three that were in large flower pots. I'v manage to get two of them to start coming back by cutting all the dead limbs and cottoning looking substance on the branches. what can i do for the other? I put root simulater on them.
|Answer from NGA
August 22, 2010
|If you found mealybugs or cottony scale insects on your gardenias, that would explain the black substance on the upper surfaces of the leaves. The black matter is called sooty mold. When sucking insects such as scales or mealybugs feed on plants they excrete a sticky substance called honeydew. As this substance ages it turns black and is called sooty mold. Once you control the insects (as you did when you pruned off the affected plant parts), the sooty mold will stop appearing. Check your patio tree for insect populations. Use Insecticidal Soap to control the insect pests, or prune off heavily infested plant parts to remove them from the plant. Then feed your gardenias with an acidified fertilizer such as Miracid. I'm sure you'll see healthy new growth in a few short weeks.
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