Looks like leaf spots caused by fungi. Shade and moisture allow them to flourish. Use good sanitation techniques to minimize their development. Water in nthe early hours of the morning. Water the soil and not the leaves. Pick up any plant debris that collects under then brush and dispose in the trash. When the plant goes dormant, dispose of the blooms and dried leaves in the trash. If the mulch is often wet, water it less often so the amount of soil moisture is not high and promotes development of fungal diseases. If your growing season is long where you live, you can apply fungicides against leaf spots but otherwise, your leaves may soon dry out as the plant does dormant so it is not worth it to apply fungicides. In that case, I would apply some fungicides next year as the humidity increases.