Canadian Plum
Prunus nigra
Family: Rosaceae
What it is like
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.
Height (m): 9
Where it is found
Thickets, stream banks and woodland edges, in alluvial soils of river valleys and on limestone hills.
Eastern N. America - New Brunswick to Manitoba, south to Iowa, Ohio and Connecticut.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 4
Fruit - raw or cooked. It can be eaten out of hand, used in pies, preserves etc, or can be dried for later use. The fruit is small and not very palatable. A sour flavour with a thick skin, though the flavour is improved tremendously if the fruit is harvested after being touched by a few frosts. The fruit is about 3cm in diameter and contains one large seed. 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. See the notes above on toxicity.
Seed: includes nuts, cereals, peas and beans.
Medicine
Rating: 1
An infusion of the inner bark has been used in the treatment of colds. An infusion of the bark has been used to settle the stomach when it will not retain food. 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.
Pectoral: Relieves respiratory diseases, a remedy for chest diseases.
Stomachic: Aids and improves the action of the stomach.
Other
Rating: 2
A green dye can be obtained from the leaves. A dark grey to green dye can be obtained from the fruit. The inner bark has been used as an astringent colour fixative in dyeing with other plants. Wood - hard, moderately heavy, close grained. It weighs 43lb per cubic foot. The tree is too small to be used commercially.
Dye: Plants that provide dyes.
Mordant: Used for making a dye more permanent, it also affects the colour of the dye.
Wood: A list of the trees and shrubs that are noted for having useful wood.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
How it is grown
Thrives in a well-drained moisture-retentive loamy soil, growing well on limestone. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present. Succeeds in sun or partial shade though it fruits better in a sunny position. Sometimes cultivated as a fruit tree in Canada and America, there are some named varieties that have been selected for their edible fruit. This species is closely related to P. americana. A bad companion for potatoes, the plum tree harbours aphids that can damage the potatoes. Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged. Plants in this genus are notably susceptible to honey fungus. Prunus americana var. nigra (Aiton) Waugh is a synonym of Prunus nigra Aiton. It may also be recorded as Prunus americana nigra. For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. A sprouting standard sending up shoots from the base. The root pattern is suckering with new plants from underground runners away from the plant.
Propagating it: Seed - requires 2 - 3 months cold stratification and is best sown in a cold frame as soon as it is ripe. Sow stored seed in a cold frame as early in the year as possible. Protect the seed from mice etc. The seed can be rather slow, sometimes taking 18 months to germinate. 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, July/August in a frame. Softwood cuttings from strongly growing plants in spring to early summer in a frame. Layering in spring.
Best place to grow: Woodland Garden Canopy; Secondary;
Habit: Tree
Hardiness: 0-0
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Moist
Things to keep in mind
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.
Its other names
Local names
Synonyms
P. americana var. nigra (Aiton) Waugh is a synonym of P. nigra Aiton