Moved into house 12 months ago. Berberis shrub (barberry) in front garden had mildew. Cut it back in autumn, shooted well, but mildew is back. What to do? Type unknown, but common. No other mildew in garden.
Berberis With Mildew
Certified GKH Gardening Expert
In addition to cutting off the affected foliage, try treating the shrub with neem oil. It's an effective fungicide as well as pesticide. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm