Q. What is the latest news on the boxwood blight.
What sprays prevent this blight and what boxwood cultivars are most affected?
The American Boxwood Society recommends this October 2018 boxwood blight update from Saunders Brothers, a grower in Virginia. The article includes information on fungicide spraying for prevention as well as what to do if an infected plant is discovered.
Boxwood blight continues to be a problem following an extraordinarily rainy growing season. The blight is caused by a fungus and the weather we have experienced for the past several growing seasons is very conducive to fungal spread. The problem with boxwoods has been made worse by the over-use of fungicides. Types of boxwood once considered blight resistant have become symptomatic.
The boxwood referred to as English is Buxus sempervirens 'Suffruticosa' and it is indeed very susceptible to blight. (While many landscapers refer to boxwood as English or American, that is not really a true difference as the “American” species actually originate in England as well.) Not all boxwoods referred to as American are blight resistant and you will also want to consider some plants that are Korean or Japanese boxwoods. The American Boxwood Society,recommend this research by the University of Vermont regarding disease resistant cultivars. This fact sheet also shows a great photo of how the disease presents itself on the plant so that you can confirm that it is fungal disease that you are seeing.
I also recommend the American Boxwood Society’s FAQ page for more general information on your plants to improve your chances with your next investment. Make sure that you discuss the growing habit of available boxwood species with your landscaper before making your selection as leaf size, branch structure, height and width can vary considerably.