Rhododendron spp.—Azalea, Rhododendron
FAMILY: Ericaceae - the Heath Family (see Kalmia)
PHENOLOGY: The azaleas and rhododendrons commonly flower in spring and early summer.
DISTRIBUTION: The genus Rhododendron can be divided into two nontechnical categories: cultivated and native plants. The cultivated plants are widely used around homes for their foral displays and, in some cases, evergreen foliage. The native plants are found in moist or wet woods, sometimes in dense colonies.
PLANT CHARACTERISTICS: Botanists recognize perhaps 800 species of Rhododendron. Included in this assemblage are azaleas, even though they usually are considered distinct by gardeners. The reader is generally familiar with cultivated rhododendrons and azaleas. The native, wild species do not differ greatly in appearance
POISONOUS PARTS: The foliage of some species is toxic. All taxa are considered potentially poisonous.
SYMPTOMS: All poisonous members of the Ericaceae produce similar effects (see Kalmia). Symptoms can include salivation, tearing, nasal discharge, vomiting, convulsion and paralysis, and loss of appetite.
POISONOUS PRINCIPLES: The complex mixture andromedotoxin is suspected, as well as the hydroquinone glucoside arbutin.
CONFUSED TAXA: Rhododendrons and azaleas are familiar plants in Pennsylvania. No confusion is readily possible, with the exception of Kalmia(see Kalmia).
SPECIES OF ANIMALS AFFECTED: Several species of Rhododendron are known to cause loss of livestock.
TREATMENT: (11a)(b); ( 1); (5); (12)