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Pieris Japonica Diseases

pieris variety carnival (close up of foliage) image by Shirley Hirst from

The pieris japonica is the name of a plant. It is also commonly known as the Japanese pieris, pieris and Japanese andromeda. The pieris japonica is part of the Ericaceae family. It is a slow-growing, broadleaf evergreen shrub that often grows to approximately 8 feet by 10 feet. The pieris japonica can be affected by numerous diseases.

Phytophthora Root Rot

Phytophtora root rot is one of the most harmful diseases that commonly affects the pieris japonica. Phytophtora root rot results in the shrub wilting and eventually dying. It dramatically decreases the volume of the plants' roots. The volume is necessary in order for the plant to absorb nutrients and plants. This disease causes the roots of plants to appear reddish brown and brittle. In some cases, water-soaked and brown cankers might appear on the soil line. These cankers emit a dark gum or fluid. Root diseases are especially common with plants that experience extremes of soil moisture, whether the soil is overly wet or overly dry.


Chlorosis is a common and problematic disease that occasionally affects the pieris japonica. With chlorosis, the foliage suffers from insufficient levels of green chlorophyll. This results in discoloration of the leaves and the leaves instead appearing yellowish in color. Chlorosis has several different possible causes, including compacted or damaged roots, improper soil drainage and deficiencies of vital nutrients like zinc, manganese and iron. This disease can be treated by adding some nutrients into the soil. However, if the soil being compacted is the case, the disease might have to be treated by tilling the soil.

Fungal Diseases

Canker disease fungi is another possible affliction that could lead to damage for the pieris japonica. Canker disease fungi can lead to dieback of the shrub's branches and stems, particularly right after times of either drought or lower temperatures. Another possible problem is leaf spot fungi, which can be destructive, particularly during springs that experience an abundance of rainfall.

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