Common Name
Japanese Pieris
Botanic Name
Pieris japonica
Plant Family
Ericaceae (Heath family)
Acidic soils of the Eastern USA.
Animals Affected
Cattle, sheep, goats,horses, camelids, dogs,cats and humans
Japanese Pieris (Pieris japonica)
Toxic Principle
Like the rhododendrons, Pieris spp. contain grayanotoxins I, II, III (polyhydroxylated diterpenes)that binds to the sodium channels of heart and skeletal muscle and nerve cells, maintaining the cells in a state of depolarization. The toxic dose of the green plant in cattle and goats is 0.2-0.6% of the animal's body weight
A genus of 7 species of evergreen shrubs, originating in North America, and Asia.Shrubs are compact and grow to 12 feet in height, with glossy green leaves. New leaves are often red in color. Some hybrids of Pieris have variegated leaves. Flower buds persist throuhout the winter, and in the spring produce dense clusters of creamy white flowers.
Excessive salivation, vomiting, and abdominal pain usually develops 6-8 hours after the plant is eaten.
Weakness, recumbency
There is no specific treatment, and if inhalation pneumonia does not occurr, animals generally recover. Activated charcoal and cathartics are indicated early in the course of poisoning. Similarly, emetics are useful in dogs and cats if the plant has been eaten in the past 2 hours.Intravenous fluid therapyis indicated along with other supportive therapy.
Cardiovascular system
Increased heart rate, ventricular tachycardia, arrhythmias
Respiratory System
Increased respiratory rate. Inhalation pneumonia is frequently the cause of death.
Nervous System
Seizures and convulsions occur in severely poisoned animals.
Reproductive System
Mummification of the fetys has been reported in goats eating Japanese pieris.
Special Notes
Honey derived from rhododendrons, Pieris and other members of the Heath family can contain toxic levels of grayanotoxin ("mad honey"), and can cause poisoning in people who eat it.
Japanese Pieris flowers
Japanese pieris flowers