Q.potted privet discoloration and leaf loss
Planted 100 potted hedges 3 months ago per instructions and enclosed with wind barrier at windy side. Leaves have turned to yellow, purple and brown. Also losing a lot of leaves. I sprayed with Blight Fungicide 4 weeks ago as suggested by friend and not sure if this has any effect. Plants were 2 to 3 feet tall when planted. I planted same amount 2 years ago at opposite side of garden and they are beautiful. Planted golden and green, every second one.
Privet, or ligustrum, are generally disease and pest free, but they are troubled by a type of fungal infection called cercospora. This is difficult to treat because not all fungicides work against it. This article has more information: http://www.clemson.edu/public/regulatory/plant_industry/pest_nursery_programs/plant_prob_clinic/fact_sheet_folder/cercospora_leaf.html
When something is wrong with your plants, the best thing you can do is to find out exactly what the problem is, and use the specific treatment for that problem. Take some samples of the affected leaves to whatever expert source is available - extension service in the US,
https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
master gardeners in the UK, Canada, and Australia. http://mastergardeners.org.uk/get-involved/find-your-nearest-master-gardener/
You can also always locate some experts by contacting the nearest botanical garden or university agriculture dept.