Dying oregon grape

Credit: iStockphoto


Q: I have established ‘Oregon grape’ (Mahonia aquifolium) in my garden. Just recently the plants have started turning a reddish colour and appear to be dying. The plants were originally under a fir tree. The dead fir tree was removed about three years ago. The site itself has otherwise not been disturbed. What is the problem?

The ‘Oregon grape’ is suffering from “sunburn.” When the dead fir was removed more light began bombarding the plant. Since Mahonia is an evergreen shrub the current and older leaves could not adapt to the sudden change in light intensity. Remove whatever dying Mahonia foliage and the newer growth emerging from the ground level should not have any further problems since they are now better accustomed to the brighter light levels.