Why do so many Pieris have a black coating in Vancouver - including mine?! The new growth is beautiful but the previous growth is covered in a black sooty like coating.
pieris japonica You can wash the sooty mold off with water or the garden hose If the problem persists apply an insecticidal soap.
The black sooty mould that people are seeing on Pieris is growing on the excrement of andromeda lacebugs. Pieris cultivars with Pieris formosa blood (i.e., P. japonica x P. formosa -- e.g., 'Firecrest', 'Forest Flame' and 'Valley Fire') are prone to infestations,
hi chris, a usefull way to wash off sooty mold is mixing i tsp dawn detergent in a quart of water. spray on, let it set for a few minutes and hose off. it may have to be done several times.
