Prunus lusitanica

Prunus lusitanica, the Portuguese laurel cherry or Portugal laurel, is a species of flowering plant in the rose family Rosaceae, native to the Iberian Peninsula, Morocco, the Macaronesian archipelagos, and the French Basque Country. The split between the subspecies (subsp. azorica, hixa, and lusitanica) is dated around the Pliocene.

Description

A dense evergreen shrub. It grows 6-10 m high. It is a broad spreading shape. The bark is dark grey-brown and smooth. The leaves are alternate. The leaves are oval and 12 cm long by 5 cm wide and with red leaf stalks. The leaves are dark and glossy green above and yellow-green underneath. They have fine teeth and long pointed tips. The flowers are white and 1 cm across and in slender sprays. There are about 20 flowers in each cluster. These are about 25 cm long. The fruit are red and turn black as they ripen. They hang on stalks. There are 3 subspecies.

Edible Uses

The fruit is probably edible when fully ripe, measuring about 8mm in diameter with one large seed. Bitter fruit should not be eaten, as bitterness indicates the presence of toxic compounds — see toxicity notes. The seed can be eaten raw or cooked, but should likewise be avoided if it tastes too bitter.

Medicinal Uses

No specific research has been recorded for this species, but all members of the genus contain amygdalin and prunasin, which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being.

Known Hazards

Although no specific mention has been seen for this species, it belongs to a genus where most, if not all members of the genus produce hydrogen cyanide, a poison that gives almonds their characteristic flavour. This toxin is found mainly in the leaves and seed and is readily detected by its bitter taste. It is usually present in too small a quantity to do any harm but any very bitter seed or fruit should not be eaten. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death.

Distribution

It is native to S.W. France, Portugal and Spain. Temperate. It can grow on chalky soils. Geelong Botanical Gardens. Kyneton Botanical Gardens. It suits hardiness zones 7-10.

Where It Grows

Australia, Britain, Central America, Europe, France, Jamaica, Mediterranean, North America, Portugal, Spain, USA, West Indies,

Cultivation

Succeeds on all soil types, though it prefers a well-drained moisture-retentive loamy soil. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present. Thrives on chalk according to other reports. Succeeds in sun or partial shade though it fruits better in a sunny position. Hardy to about -20°c. A very ornamental plant, there are some named varieties selected for their ornamental value. Grows well in a woodland. Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged. Plants are susceptible to silver leaf disease. Plants in this genus are notably susceptible to honey fungus. The flowers are pleasantly scented. Any trimming is best done with secateurs in August. Plants are very tolerant of pruning.

Propagation

Seed requires 2–3 months of cold stratification and is best sown in a cold frame as soon as it is ripe. Stored seed should be sown in a cold frame as early in the year as possible. Protect seed from mice. Germination can be slow, sometimes taking 18 months. Prick out seedlings into individual pots when large enough to handle, grow on in a greenhouse or cold frame through their first winter, and plant out in late spring or early summer the following year. Cuttings of half-ripe wood with a heel can be taken in July/August in a frame. Cuttings of mature wood can be taken in October in a sheltered north-facing border outdoors. Layering can be done in spring.

Other Uses

This plant works well as a low windbreak and can also be grown as a medium to tall hedge or used for topiary. A green dye can be obtained from the leaves, and a dark grey to green dye from the fruit.

Notes

There are about 200 Prunus species. It can be invasive.

Synonyms

References (11)

• Blamey, M and Grey-Wilson, C., 2005, Wild flowers of the Mediterranean. A & C Black London. p 77
• Coombes, A.J., 2000, Trees. Dorling Kindersley Handbooks. p 266
• Cundall, P., (ed.), 2004, Gardening Australia: flora: the gardener's bible. ABC Books. p 1095
• Harris, E & J., 1983, Field Guide to the Trees and Shrubs of Britain. Reader's Digest. p 98
• Hibbert, M., 2002, The Aussie Plant Finder 2002, Florilegium. p 241

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