Kalmia latifolia L., Sp. Pl. 1: 391. 1753.
* Chamaedaphne latifolia (L.) Kuntze, Revis. Gen. Pl. 2: 388. 1891.
* Kalmia latifolia f. alba (Raf.) Rehder, Rhodora 12: 2. 1910.
* Kalmia latifolia f. fuscata (Rehder) Rehder, Rhodora 12: 2. 1910.
* New York Metropolitan Flora Project. Brooklyn Botanical Garden. Accessed 2009 June 14 .
Kalmia latifolia, commonly called Mountain-laurel or Spoonwood, is a species flowering plant in the blueberry family, Ericaceae, that is native to the eastern United States. Its range stretches from southern Maine south to northern Florida, and west to Indiana and Louisiana. Mountain-laurel is the state flower of Connecticut and Pennsylvania. It is the namesake of the city of Laurel, Mississippi (founded 1882).
It is an evergreen shrub growing to 3–9 m tall. The leaves are 3–12 cm long and 1–4 cm wide. Its flowers are round, ranging from light pink to white, and occurring in clusters. There are several named cultivars today that have darker shades of pink, near red and maroon pigment. It blooms in May and June. All parts of the plant are poisonous. Roots are fibrous and matted.
The plant is naturally found on rocky slopes and mountainous forest areas. It thrives in acidic soil, preferring a soil pH in the 4.5 to 5.5 range. The plant often grows in large thickets, covering great areas of forest floor. In North America it can become tree sized on undeveloped mountains of the Carolinas but is a shrub farther north. The species is a frequent component of oak-heath forests. 
It is also known as Ivybush, Calico Bush, Spoonwood (because native Americans used to make their spoons out of it), Sheep Laurel, Lambkill and Clamoun.
The plant was first recorded in America in 1624, but it was named after Pehr Kalm, who sent samples to Linnaeus in the 18th century.
Cultivation and uses
The plant was originally brought to Europe as an ornamental plant during the 18th century. It is still widely grown for its attractive flowers. Numerous cultivars have been selected with varying flower color. Many of the cultivars have originated from the Connecticut Experiment Station in Hamden and from the plant breeding of Dr. Richard Jaynes. Jaynes has numerous named varieties that he has created and is considered the world's authority on Kalmia latifolia. 
A little known American use of the plant was in the making of arbors for early wooden-works clocks.
Mountain laurel is a food plant of last resort for gypsy moth caterpillars, utilized only during outbreaks when moth densities are extremely high.
The branches of mountain laurel trees are well suited for use as a handrail or guard rail.  When used in a handrail, smaller diameter branches of less than 1.5 inches are preferred. Mountain laurel branches larger in diameter than 1.5 inches are used in exterior structures, pergolas, gazebos, bridge guardrails and more. Rustic mountain furniture, from chairs and tables to bed frames and bureaus, can be crafted out of this versatile wood.
Mountain-laurel is poisonous to several different animals due to andromedotoxin and arbutin, including horses, goats, cattle, sheep, and deer. It is not toxic to dogs, cats, or small household pets. The green parts of the plant, flowers, twigs, and pollen are all toxic, and symptoms of toxicity begin to appear about 6 hours following ingestion. Poisoning produces anorexia, repeated swallowing, profuse salivation, depression, uncoordination, vomiting, frequent defecation, watering of the eyes, irregular or difficulty breathing, weakness, cardiac distress, convulsions, coma, and eventually death. Autopsy will show gastrointestinal irritation and hemorrhage.
1. ^ a b Keeler, Harriet L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scribner's Sons. pp. 186–189.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License