Swamp Laurel, Bog laurel
Kalmia polifolia

Family: Ericaceae

What it is like

Kalmia polifolia is an evergreen Shrub growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in). See above for USDA hardiness. It is hardy to UK zone 2. It is in leaf all year, in flower in April, and the seeds ripen in September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 0.5

Where it is found

Cold peat bogs and other wet places.

Northern N. America - Newfoundland to Hudson Bay, southwards. Nat. in Britain in a bog in Surrey.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Medicine

Rating: 2

Swamp 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. It is little, it at all, used in modern herbalism though the leaves are a good external treatment for many skin diseases and inflammation. The leaves are astringent and sedative. They are used externally to make a poultice or a wash in the treatment of many skin diseases, open sores, wounds that will not heal and inflammation. Used internally, the leaves have a splendid effect in the treatment of active haemorrhages, diarrhoea and flux. They should be used with great caution however, and only under the supervision of a qualified practitioner. See the notes above on toxicity.

Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.

Narcotic: Relieves pain, induces drowsiness and gives a sense of well-being.

Poultice: A moist, usually warm or hot, mass of plant material applied to the skin in the treatment of burns etc.

Salve: Soothes and heals damaged skin.

Sedative: Gently calms, reducing nervousness, distress and irritation.

Other

Rating:

How it is grown

Requires an acid humus-rich soil, succeeding in part shade or in full sun in cooler areas. Prefers almost full sun. Dislikes dry soils, requiring cool, permanently moist conditions at the roots. Succeeds in open woodland or along the woodland edge. A very cold-hardy plant, tolerating temperatures down to about -30°c. A very ornamental plant, there are some named varieties. Pruning is not normally necessary.

Propagating it: Seed - surface sow in late winter in a cool greenhouse in light shade. 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. Plant them out into their permanent positions in early summer. The seed is dust-like and remains viable for many years. Cuttings of half-ripe wood, August in a frame. Very poor results unless the cuttings are taken from very young plants. Layering in August/September. Takes 18 months. 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.

Best place to grow: Woodland Garden Dappled Shade; Shady Edge; Bog Garden;

Habit: Shrub

Hardiness: 0-0

Growth:

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

The foliage is poisonous to animals. The whole plant is highly toxic.

Its other names

Local names

Synonyms

K. glauca.