I have a large shrub which has become a hedge. Checking at a nursery I believe it is a photinia. The bush is many years old. The leaves, old and new, are developing brown spots which spread and they eventually fall off. I have lost much of my leaves and notice that a neighbour's 2 smaller shrubs have lost all their leaves. I have been told the cause is likely a fungus and a systemic fungicide was recommended. Will the tree recover if this works. If not I have a large hole to fill. Thanks, Bob.
Photinia is an evergreen shrub that prefers rich, well-drained soil, sunshine and plenty of moisture in the the spring and summer in Vancouver. Air circulation is also important for maintaining the plant's health. Fungal problems usually only arise in photinia where there is overhead watering -- especially drips from trees overhead -- shade and poor circulation. Poorly drained soil is often a common factor in pest and disease susceptibility, as well. When photinias get to be large shrubs, they require increasing amounts of moisture, and if they run out, this puts the plant under significant stress. Before leaves drop, they often turn brown in patches. In other words, insufficient moisture could be causing the leaf drop. Black spot -- the same disease that affects roses -- is the most common fungal problem on photinia locally. Its symptoms include small brown or black spots with a purple halos that enlarge and coalesce, and leaf drop. Once established in the shrub, it is difficult to eradicate, especially where air circulation is poor and leaf litter is hard to remove. In the event that the plant is infected with a fungus, removing dropped leaves from around the plant, increaing air circulation and maintaining soil moisture (by regular, deep watering) and fertility (by mulching) will probably do more to correct the situation than applications of fungicides (despite what well-meaning pesticide salespeople may recommend).
