About

Kalmia latifolia, the mountain laurel, calico-bush, or spoonwood, is a flowering plant and one of the 10 species in the genus of Kalmia belonging to the heath(er) family Ericaceae. It is native to the eastern United States. Its range stretches from southern Maine to northern Florida, and west to Indiana and Louisiana. Mountain laurel is the state flower of Connecticut and Pennsylvania. It is the namesake of Laurel County in Kentucky, the city of Laurel, Mississippi, Mount Laurel, New Jersey, and the Laurel Highlands in southwestern Pennsylvania.

How to grow it

The plant was originally brought to Europe as an ornamental plant during the 18th century. It is still widely grown for its attractive flowers and year-round evergreen leaves. Elliptic, alternate, leathery, glossy evergreen leaves (to 5" long) are dark green above and yellow green beneath and reminiscent of the leaves of rhododendrons. All parts of this plant are toxic if ingested. 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.

In the UK the following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:

Safety

Mountain laurel is poisonous to several animals, including horses, goats, cattle, deer, monkeys, and humans, due to grayanotoxin and arbutin. The green parts of the plant, flowers, twigs, and pollen are all toxic, including food products made from them, such as toxic honey that may produce neurotoxic and gastrointestinal symptoms in humans eating more than a modest amount. Symptoms of toxicity begin to appear about 6 hours following ingestion. Symptoms include irregular or difficulty breathing, anorexia, repeated swallowing, profuse salivation, watering of the eyes and nose, cardiac distress, incoordination, depression, vomiting, frequent defecation, weakness, convulsions, paralysis, coma, and eventually death. Necropsy of animals who have died from spoonwood poisoning show gastrointestinal hemorrhage.

Where it grows

The plant is naturally found on rocky slopes and mountainous forest areas. It thrives in acid 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 the Appalachians, it can become a tree, but is a shrub farther north. The species is a frequent component of oak-heath forests. In low, wet areas it grows densely, but in dry uplands has a more sparse form. In the southern Appalachians, laurel thickets are referred to as "laurel hells” or “laurel slicks” because it is nearly impossible to pass through one.

Uses

The Cherokee use the plant as an analgesic, placing an infusion of leaves on scratches made over location of the pain. They also rub the bristly edges of ten to twelve leaves over the skin for rheumatism, crush the leaves to rub brier scratches, use an infusion as a wash "to get rid of pests", use a compound as a liniment, rub leaf ooze into the scratched skin of ball players to prevent cramps, and use a leaf salve for healing. They also use the wood for carving.

Other Kalmia plants

Sheep laurel · Bog laurel