I’m looking for detailed information on how well Pacific wax myrtle (Morella aka Myrica californica) performs in northwestern Washington. Also, when is the best time to prune this shrub for renovation?
Morella californica is native to the Pacific Northwest (including the southern part of the Washington coast), and is generally recommended for planting in our area. It’s very fast-growing during the first 10 years after planting, and is tolerant of drought, wind, and salt spray. It’s also tolerant of varying soil conditions, and takes well to pruning.
However, during the past decade, it’s been found to be susceptible to a leaf-blight disease, Phytophthora taxon morella. Many Phytophthora species are primarily root-rot diseases, but this one is a foliar disease. It’s important to remove affected growth and clean up fallen leaves. New leaves produced in late fall and winter are very susceptible, so pruning should be done in spring. Infections tend to fall off as the weather warms. In the past, California wax myrtle was considered both sun and shade-tolerant, but plants growing in shady conditions are more susceptible to this disease than plants growing in open conditions.