|What causes black splotches on my aucuba japonica shrub?|
|Foliage problems, such as wilting or necrotic spotting, may reflect a root problem or other stress condition. Aucubas grow best in shaded areas. Plants growing in exposed areas may develop black leaf spots or blotches. A dieback characterized by total decay of leaves, petioles, and branches often occurs on exposed plants in early spring. This can be caused by exposure to full sun combined with cold injury.
To control foliar problems, plant aucubas in partially shaded areas. Give exposed plants some protection during cold winter weather. Promptly prune out dead branches several inches below any sign of discoloration. Avoid excess fertilizer, especially during late summer and fall.
Following the above recommendations will help your Aucuba regain its health. Best wishes with your garden!