I have 2 gardenias which have become covered with a black mould. They are planed in a garden which gets very little sun. How do I get rid of this mould?
28 May 2019 07:58 PM
The mould you have on your gardenias is likely to be Sooty Mould. Sooty Moulds are fungi which cover plant leaves, stems and twigs in a black sticky substance. In almost all cases, Sooty Mould is secondary to an infestation of insects that secrete honeydew. At some stage you would have had either aphids, mealybugs, scale (more likely the culprit on gardenias)on your plants. By treating the insects, you will remove the source of the honeydew and dry up the Sooty Mould, which will eventually fall or wash off the foliage. The mould itself does not feed on the plant, however as it covers the leaf surface, it is blocking light and reducing photosynthesis, essential for plant growth. Treat the sap sucking insect by using PestOil. This product will block the breathing pores of the insect causing suffocatin and rapid death. The PestOil will also help to lift the Sooty Mould from the leaf which will eventually be washed off with rain water.
From your friends at Yates Gardening