Q. Is Japanese Holly a good substitute for Boxwood?
Boxwood (Buxus) has always been a popular plant for hedges, parterres and foundation plantings, however it is becoming less used because of its susceptibility to a fungus disease called Box Blight. A number of alternative plants are available and Japanese holly (Ilex crenata) is probably the one that resembles boxwood most closely. Like boxwood, it is tolerant to severe pruning making it suitable for hedges. Many varieties are available with different growth characteristics and culture requirements. Japanese holly also tends to be cheaper than boxwood at many nurseries.
You do not necessarily need to avoid boxwood in your garden. If boxwood is taken care of properly it will make a fine hedge. See the proper care techniques for boxwood below to prevent disease problems.
Preventing foliage diseases of English boxwood
Mature English boxwood is prone to developing overly dense foliage, often with fatal results. The dense growth reduces sunlight into the center of the shrub, which causes premature foliage drop and weakens the plant. The resulting leaf debris accumulates in the lower branches, causing abundant and vigorous aerial roots to grow in this moist and dark environment. Eventually, the exposed aerial roots will die, shocking the weakened plant.
When planting, give each plant room for sunlight and good air circulation. Thin English boxwood in late fall if the foliage completely hides the view of the interior branches. To thin, using sharp bypass pruners, reach inside about 6 inches, and remove a twig. Continue to prune until the small interior twigs become intermittently visible, along with the older, light green interior leaves. When pruning is completed, the shape and size of the boxwood should look unchanged. Use clippings for propagation, if desired.
For more detailed information on growing boxwood, refer to our boxwood FAQ.
Courtesy of the NYBG Plant Information Service