Kalmia latifolia

Kalmia latifolia, the mountain laurel, calico-bush,

Description

Kalmia latifolia is an evergreen shrub growing tall. The leaves are 3–12 cm long and 1–4 cm wide. The flowers are pentagonal, ranging from light pink to white, and occur in clusters. There are several named cultivars that have darker shades of pink, red and maroon. It blooms in May and June. All parts of the plant are poisonous. The roots are fibrous and matted.

File:Mountain Laurel Kalmia latifolia 'Olympic Wedding' Leaves and Buds 2575px.jpg|K. latifolia leaves and early buds

File:Buberel unknown flower 12.jpg|Flower buds

File:Kalmia latifolia species.jpg|Beginning to bloom

File:Mountain Loral Flowers.jpg|Full bloom

File:Mountain Laurel Kalmia latifolia 'Olympic Wedding' Young Old Flowers 3264px.jpg|Blooming and wilted flowers on the same flower head

File:Bee on a mountain laurel on Occoneechee Mountain.jpg|Bee pollinating mountain laurel on Occoneechee Mountain

2015-06-07-17h21m33 (31791324900).jpg|Kalmia latifolia in North Smithfield, Rhode Island

File:Kalmia latifolia 563990074.jpg|Fruits

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Taxonomy

thumb|The [[Type_(biology)#In_botany|type of Kalmia latifolia in a botanical illustration]]

Kalmia latifolia was named and described by the renowned Swedish botanist Carl Linnaeus in 1753. In his description, Linnaeus referred to an earlier description and illustration of Chamaedaphne foliis published by the English naturalist Mark Catesby in 1743. Catesby's illustration was designated as the lectotype of Kalmia latifolia in 1993.

Distribution and habitat

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. 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.

Ecology

Kalmia latifolia has been marked as a pollinator plant, supporting and attracting butterflies and hummingbirds.

It is also notable for its unusual method of dispensing its pollen. As the flower grows, the filaments of its stamens are bent and brought into tension. When an insect lands on the flower, the tension is released, catapulting the pollen forcefully onto the insect. Experiments have shown the flower capable of flinging its pollen up to 15 cm. Physicist Lyman J. Briggs became fascinated with this phenomenon in the 1950s after his retirement from the National Bureau of Standards and conducted a series of experiments in order to explain it.

Etymology

Kalmia latifolia is also known as ivybush or spoonwood (because Native Americans used to make their spoons out of it).

The plant was first recorded in America in 1624, but it was named after the Finnish explorer and botanist Pehr Kalm (1716–1779), who sent samples to Linnaeus.

The Latin specific epithet latifolia means "with broad leaves" – as opposed to its sister species Kalmia angustifolia, "with narrow leaves".

Despite the name "mountain laurel", Kalmia latifolia is not closely related to the true laurels of the family Lauraceae.

Cultivation

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:

'Freckles' – pale pink flowers, heavily spotted
'Little Linda' – dwarf cultivar to
'Olympic Fire' – red buds opening pale pink
'Pink Charm'

File:Kalmia latifolia Clementine Churchill.jpg|'Clementine Churchill' in the Real Jardín Botánico de Madrid

File:Kalmia latifolia Little Linda 0zz.jpg|'Little Linda'

File:Kalmia latifolia 'Minuet' kz01.jpg|'Minuet' in Christchurch Botanic Gardens

File:Kalmia latifolia 'Olympic Fire' 6471.jpg|'Olympic Fire' in the Dorothy Clive Garden, England

File:Kalmia latifolia Pinwheel 1zz.jpg|'Pinwheel' in Brookside Gardens, Maryland

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Wood

thumb|alt=handrail made with mountain laurel branches|Wood railing section made with mountain laurel branches

The wood of the mountain laurel is heavy and strong but brittle, with a close, straight grain. It has never been a viable commercial crop, as it does not grow large enough, Root burls were used for pipe bowls in place of imported briar burls unattainable during World War II. It can be used for handrails or guard rails.

Toxicity

Mountain laurel is poisonous to several animals, including horses, goats, cattle, deer, monkeys, and humans, and arbutin. The green parts of the plant, flowers, twigs, and pollen are all toxic, 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, 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.

References

Bibliography

External links

Connecticut Botanical Society Profile: Kalmia latifolia
Kalmia latifolia images at bioimages.vanderbilt.edu