
Prunus lusitanica
Prunus lusitanica
Safety & Hazards
The plant (especially the seed and young shoots) contains cyanogenic glycosides, especially amygdalin and prunasin. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[1]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted. In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[2]. The fruits and flowers of most members of this genus generally have low or very low concentrations of this toxin, though the seeds and young shoots can contain much higher levels. The levels of toxin can be detected by the level of bitterness:- for example sweet tasting almond seeds are a major food crop and are often eaten in quantity, whilst bitter tasting almond seeds are used as a flavouring (in marzipan for example) but are not usually eaten on their own. In general, it can be considered safe to eat any fruit or seed from species in this genus that either have a sweet flavour or are slightly bitter. Great caution should be taken, however, if the flavour is moderately to very bitter[PFAF].
Cultivation Details
Prunus lusitanica is fairly cold-hardy, when dormant it can tolerate temperatures down to about -20°c[3]. Succeeds on all soil types[4], though it prefers a well-drained moisture-retentive loamy soil[5, 6]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[7]. Thrives on chalk according to other reports[8, 9, 6]. Succeeds in sun or partial shade though it fruits better in a sunny position[5, 6]. A very ornamental plant[7], there are some named varieties selected for their ornamental value[9]. Grows well in a woodland[4]. Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[1]. A serious defect of the Portugal laurel is that it is susceptible to Silver Leaf disease (Stereum purpureum)[5]. Plants in this genus are notably susceptible to honey fungus[6]. The flowers are pleasantly scented[9]. Any trimming is best done with secateurs in August[9]. Plants are very tolerant of pruning.
Propagation
Seed - requires 2 - 3 months cold stratification and is best sown in a cold frame as soon as it is ripe[6]. Sow stored seed in a cold frame as early in the year as possible[6]. Protect the seed from mice etc. The seed can be rather slow, sometimes taking 18 months to germinate[10]. Prick out the seedlings into individual pots when they are large enough to handle. Grow them on in a greenhouse or cold frame for their first winter and plant them out in late spring or early summer of the following year. Cuttings of half-ripe wood with a heel, mid summer in a frame[5, 6]. Cuttings of mature wood, early autumn in a sheltered north facing border outdoors[10]. Layering in spring. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Prunus+lusitanica>
Pollinators
Insects
References
- [1]Encyclopaedia of Herbs and their Uses. — Bown. D. · Dorling Kindersley, London. · 1995 · ISBN 0-7513-020-31 ↩︎A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.
- [2]Poisonous Plants of North Carolina — http://www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm ↩︎An excellent concise but comprehensive guide to toxic plants that grow in N. Carolina. It lists even those plants that are of very low toxicity, including several well-known food plants such as carrots and potatoes.
- [3]Shrubs. — Phillips. R. & Rix. M. · Pan Books · 1989 · ISBN 0-330-30258-2 ↩︎Excellent photographs and a terse description of 1,900 species and cultivars.
- [4]Plants for Shade. — Knight. F. P. · Royal Horticultural Society. · 1980 · ISBN 0-900629-78-9 ↩︎A small but informative booklet listing plants that can be grown in shady positions with a few cultivation details.
- [5]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
- [6]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
- [7]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
- [8]Seed Manual for Ornamental Trees and Shrubs. — Gordon. A. G. and Rowe. D. C. F. · HMSO; London · 1982 · ISBN 0-11-710152-4 ↩︎Very comprehensive guide to growing trees and shrubs from seed. Not for the casual reader.
- [9]Ornamental Shrubs, Climbers and Bamboos. — Thomas. G. S. · Murray · 1992 · ISBN 0-7195-5043-2 ↩︎Contains a wide range of plants with a brief description, mainly of their ornamental value but also usually of cultivation details and varieties.
- [10]The Reference Manual of Woody Plant Propagation. — Dirr. M. A. and Heuser. M. W. · Athens Ga. Varsity Press · 1987 · ISBN 0942375009 ↩︎A very detailed book on propagating trees. Not for the casual reader.
- [11]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
- [12]Nature's Colors - Dyes from Plants. — Grae. I. · MacMillan Publishing Co. New York. · 1974 · ISBN 0-02-544950-8 ↩︎A very good and readable book on dyeing.
- [PFAF]Plants for a Future — pfaf.org ↩︎