Buxus microphylla japonica, commonly known as Japanese Boxwood, is a compact mounding evergreen shrub. It has a symmetrical form and grows 3 to 6 feet tall. Japanese Boxwoods are used as hedges, borders around flowerbeds or in mass plantings. They can be left natural or be pruned in various shapes to complement any garden style.
Japanese Boxwoods are susceptible to several fungal diseases, including root rot caused by Phytophthora. Root rot causes poor growth, which results in pale colored leaves and eventually the death of the infected plant. Macrophoma fungus causes brown spots on the foliage of Japanese Boxwoods, as well as brown leaf edges and tips. Boxwoods with Volutella leaf and stem blight have cream to light pink fruiting bodies on the infected leaves and twigs. The leaves also turn bronze, and then brown. Stunted and poor growth are some signs of nematode infestation on Japanese boxwoods. Some nematodes that attack boxwoods are boxwood spiral, lesion, root knot and ring nematodes.
Leaf miners are the most damaging pest of Japanese boxwoods. They cause irregular blisters or swellings on the underside of the foliage, and affected leaves turn off-color and drop off early. Boxwood mites are common on Japanese boxwoods and make tiny scratch-like marks on the upper side of the leaves, while boxwood psylla cause stunted twigs and cupped leaves.
The foliage of Japanese boxwoods is easily burned by the hot afternoon sun. The plants should be planted where they are shaded in the afternoon to prevent scorching. Japanese boxwoods are also prone to winter damage, such as discolored foliage, dead branches, and sunken areas in the bark of crotches and at ground level. The shrubs should be protected from the winter wind and extreme cold to prevent these problems.
The sap of Japanese boxwoods can cause skin irritation, while the the leaves are mildly toxic if eaten. The symptoms of poisoning include nausea, vomiting, diarrhea, dizziness and convulsions.