The type of climate makes a big difference in using bleach as a power washing cleaner. I power wash in Atlanta, Georgia and the climate is brutal. High humidty ccoupled with rain breeds algae and mildew. I use bleach and have not had any complaints from my customers. Down stream chemical injecters with control flow safely mix the bleach with h2o. Throughly wetting down all plants close to the surfaces to clean will elimate any damages to them. However Japaneese maples are very delicate and require covering.