Canadian Plum

Prunus nigra

Physical Characteristics

Prunus nigra is a deciduous Tree growing to 9 m (29ft 6in). See above for USDA hardiness. It is hardy to UK zone 2. It is in flower in April, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Distribution

Eastern N. America - New Brunswick to Manitoba, south to Iowa, Ohio and Connecticut.

Habitats

Woodland Garden Canopy; Secondary;

Edible Uses

Edible Parts: Fruit Seed Edible Uses: Fruit - raw or cooked[82, 159]. It can be eaten out of hand, used in pies, preserves etc, or can be dried for later use[171, 183, 226, 257]. The fruit is small and not very palatable[171]. A sour flavour with a thick skin[229], though the flavour is improved tremendously if the fruit is harvested after being touched by a few frosts[226]. The fruit is about 3cm in diameter and contains one large seed[200]. Seed - raw or cooked. The seed contains prussic acid and there have been cases recorded of children dying after eating fruits without removing the stones[226]. See the notes above on toxicity.

Medicinal Uses

Pectoral Stomachic An infusion of the inner bark has been used in the treatment of colds[257]. An infusion of the bark has been used to settle the stomach when it will not retain food[257]. Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances 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[238].

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.