Practical
Plants

Kalmia latifolia

Mountain Laurel

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Taxonomy and growth

Family
Ericaceae
Genus
Kalmia
Life cycle
perennial
Foliage
evergreen
Woodiness
woody
Height
3 m
Spread
3 m
Fertility
Bees
Flower type
hermaphrodite
Pollinators
Bees

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

The foliage is poisonous to animals[8][17][18]. The whole plant is highly toxic[9]. Cases of poisoning have occurred when livestock or game birds have been eaten after they have ingested this plant[11].

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

Mountain laurel is a very poisonous narcotic plant the leaves of which were at one time used by some native North American Indian tribes in order to commit suicide[13]. Because of its toxicity, it is a remedy that is seldom used in modern herbalism[11], but the leaves have been used externally in herbal medicine and are a good remedy for many skin diseases and inflammation[13]. The leaves are analgesic, astringent, disinfectant, narcotic, salve and sedative[12]. An infusion of the leaves is used as a disinfectant wash and liniment to treat pain, scratches, rheumatism, inflammations and to get rid of body parasites[12]. Used internally, the leaves have a splendid effect in the treatment of active haemorrhages, diarrhoea and flux[13][8][16]. They are also used in the treatment of syphilis, inflammatory fevers, neuralgia, paralytic conditions, tinnitus and angina[11]. The leaves should be used with great caution however, and only under the guidance of a qualified practitioner[11]. Excess doses cause vertigo, headache, loss of sight, salivation, thirst, nausea, palpitations, slow pulse and difficulty in breathing[11]. See also the notes above on toxicity.

Product or use
Analgesic
Product or use
Astringent
Product or use
Narcotic
Product or use
Salve
Product or use
Sedative
Product or use
Skin

Material uses

A yellow-tan dye is obtained from the leaves[1]. The plant can be grown as an informal hedge[6]. Wood - heavy, hard, strong but rather brittle. It weighs 44lb per cubic foot and is used for making small implements, tool handles etc[8][15][16][20][10]. The roots are used to make spoons etc, these are fashioned when the wood is green and soft, when dry they become very hard and smooth[7]. The wood is a good fuel[15][16].

Product or use
Dye
Product or use
Wood

Ecology and functions

Hedge

Environment

Range
Eastern N. America - New England to New York south to W. Florida.
Habitat
Rich rocky, or dry gravelly woods in the shade of deciduous trees, and swamps in acid soils[14]. Prefers sandy or rocky soils[10].
Light
full sun
Shade tolerance
light shade
Water
moderate
Hardiness
Zone 4+
Soil textures
sandy, loamy, clay
Soil pH
very acid, acid
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - surface sow in late winter in a cool greenhouse in light shade[19][3]. Prick out the young seedlings into individual pots as soon as they are large enough to handle. The seedlings are rather sensitive to damping off, so water them with care, keep them well-ventilated and perhaps apply a fungicide such as garlic as a preventative. Grow the young plants on in light shade and overwinter them in the greenhouse for their first winter[19]. Plant them out into their permanent positions in early summer. The seed is dust-like and remains viable for many years[3]. Cuttings of half-ripe wood, August in a frame. Very poor results unless the cuttings are taken from very young plants[2][19]. Layering in August/September. Takes 18 months[19]. The plants can also be dug up and replanted about 30cm deeper in the soil to cover up some of the branches. The plant can then be dug up about 12 months later when the branches will have formed roots and can be separated to make new plants[6].

Cultivation

Requires an acid humus-rich soil, succeeding in part shade[4] or in full sun in cooler areas. Prefers almost full sun[2]. Dislikes dry soils[4], requiring cool, permanently moist conditions at the roots[8]. Succeeds in open woodland or along the woodland edge[6]. Plants are very cold-hardy, tolerating temperatures down to about -30°c[5]. A very ornamental plant[2], there are many named varieties[4]. This species is not very easy to grow well in Britain, it probably prefers a more continental climate[2]. This species is the state flower of Connecticut[11]. Slow to rejuvenate if the plant is cut back[6].

References

  1. Coon. N. The Dictionary of Useful Plants. Rodale Press 1975-00-00 ISBN 0-87857-090-x

    ↩

  2. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2↩3↩4

  3. Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987-00-00 ISBN 0942375009

    ↩1↩2

  4. Thomas. G. S. Ornamental Shrubs, Climbers and Bamboos. Murray 1992-00-00 ISBN 0-7195-5043-2

    ↩1↩2↩3

  5. Phillips. R. & Rix. M. Shrubs. Pan Books 1989-00-00 ISBN 0-330-30258-2

    ↩

  6. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4

  7. Coffey. T. The History and Folklore of North American Wild Flowers. Facts on File. 1993-00-00 ISBN 0-8160-2624-6

    ↩

  8. Lust. J. The Herb Book. Bantam books 1983-00-00 ISBN 0-553-23827-2

    ↩1↩2↩3↩4

  9. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

    ↩

  10. Britton. N. L. Brown. A. An Illustrated Flora of the Northern United States and Canada Dover Publications. New York. 1970-00-00 ISBN 0-486-22642-5

    ↩1↩2

  11. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩1↩2↩3↩4↩5↩6

  12. Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998-00-00 ISBN 0-88192-453-9

    ↩1↩2

  13. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3

  14. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

    ↩

  15. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2

  16. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩1↩2↩3

  17. Frohne. D. and Pf�nder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984-00-00 ISBN 0723408394

    ↩

  18. Cooper. M. and Johnson. A. Poisonous Plants in Britain and their Effects on Animals and Man. HMSO 1984-00-00 ISBN 0112425291

    ↩

  19. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

    ↩1↩2↩3↩4

  20. Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965-00-00 ISBN 0-486-20278-X

    ↩

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