A Technical Report from The Bartlett Tree Research Laboratories
Research that evaluated resistance of boxwood species and varieties to boxwood blight indicates that resistance is largely related to geographic origin of the plant. Asian species generally exhibit greatest resistances while European species show the greatest susceptibility. Hybrids between Asian and European plants exhibit intermediate resistance. Form and size also appears to have some influence on blight susceptibility. Boxwood selections with compact forms that exhibit slow growth are generally more susceptible than cultivars that have an open and larger form. The boxwood species and cultivars in this report exhibited the highest level of resistance in research conducted by North Carolina State University. Unless noted, these selections are suitable in hardiness zones 6 through 8.