How do I control black soot on my lavendar leaves?
How do I get rid of it or is the plant dead.
Without seeing the damage I can only "guessimate" the black sooty stuff on the leaf is either Sooty Mould arising from a sap sucking insect such as mealy bug or scale. Use PestOil for a fungal problem. Fungus will cause wilted black leaves where the plant is dying back. Overly wet soil conditions or high humidity can lead to this fungus. Treatment involves cutting back the diseased areas. However, once started, it may be too late to save a plant suffering from this condition. Take some cuttings from the remaining healthy sections in hope of producing a new plant.
Answered: 12 Jul, 2019