Q.Pittosporum – Yellowing And Brown Spots
Not sure if this is a watering, nutrient or fungus issue, or some combination. Some plants are green, others have yellow leaves, some yellow leaves have brown spots and some green leaves have brown spots. My neighbor waters them twice weekly for short period of time. I think a longer, once weekly watering would be better, maybe some iron and magnesium, and maybe some copper fungus spray? (Organic non-toxic solutions only please.) Thank you!
Certified GKH Gardening Expert
This appears to be Alternaria spotting. This needs to be treated with a fungicide containing copper.
I would only water when the soil is completely dry down to about 2 or 3 inches rather than on schedule, and keep all infected and dead debris completely away from the area. Make sure to water the soil directly, and not the plants foliage, when possible.
Here are some articles that will help: