Beach Plum, Graves' plum
Prunus maritima
Family: Rosaceae
What it is like
Prunus maritima is a deciduous Shrub growing to 2.5 m (8ft 2in). See above for USDA hardiness. It is hardy to UK zone 3. It is in flower in May. 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 cannot grow in the shade. It prefers dry or moist soil. The plant can tolerate maritime exposure.
Height (m): 2.5
Where it is found
Light gravelly or sandy soils near the coast.
Eastern N. America - New Brunswick to Virginia.
Conservation Status:
Countries/locations it is found in
Australia, Canada, North America, USA,
How it is used
Food
Rating: 4
Fruit - raw or cooked. Very variable in quality, the best forms are sub-acid to sweet, the fruit can be eaten out of hand, used in pies, preserves etc or be dried for later use. The fruit is about 15mm in diameter and contains one large seed. Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity.
Seed: includes nuts, cereals, peas and beans.
Medicine
Rating: 1
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.
Other
Rating: 3
A green dye can be obtained from the leaves. A dark grey to green dye can be obtained from the fruit. Plants have extensive root systems and can be used for binding sand along the coast.
Dye: Plants that provide dyes.
Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
How it is grown
Thrives in a well-drained moisture-retentive loamy soil, doing well on limestone11, 200]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present. Requires a sunny position. Tolerates maritime exposure. The beach plum is cultivated for its edible fruit in N. America, there are some named varieties. The fruit is often sold in local markets and the plant is of potential commercial importance. The fruit seldom ripens when grown in the interior of America. The cultivar 'Eastham' has large well-flavoured fruit and is a heavy cropper. 'Hancock' is an early ripening form with sweet juicy fruit. 'Squibnocket' is of high quality and is also a good sand binder. 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. The plant is heat tolerant in zones 6 through 1. (Plant Hardiness Zones show how well plants withstand cold winter temperatures. Plant Heat Zones show when plants would start suffering from the heat. The Plant Heat Zone map is based on the number of "heat days" experienced in a given area where the temperature climbs to over 86 degrees F (30°C). At this temperature, many plants begin to suffer physiological damage. Heat Zones range from 1 (no heat days) to 12 (210 or more heat days). For example Heat Zone. 11-1 indicates that the plant is heat tolerant in zones 11 through 1.) 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 clumping plant, forming a colony from shoots away from the crown but with a limited spread. 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 Sunny Edge; Dappled Shade; South Wall. By. West Wall. By.
Habit: Shrub
Hardiness: 3-7
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Dry, 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.