The taxonomic history of Prunus is long and complicated, in part due to the economic value of its fruit crops and also the ease with which some species hybridize. Here, Prunus is circumscribed in its broad sense based on the argument that when viewed on a worldwide scale, the morphologic discontinuities among the segregate genera diminish and they overlap with one another. Included here are species that have at times been placed in the genera Amygdalus, Armeniaca, Cerasus, Laurocerasus, Padus, and Persica.
At the species level, Prunus has been the object of the usual combining and splitting common among taxonomists with different philosophies and opinions. In particular, over-reliance on the indument of various vegetative and floral parts has led to the naming of numerous species and infraspecific taxa. Similarly, too much has been made of fruit colour and palatability in naming taxa of Prunus. It is very likely that, as molecular and genetic data are analyzed and, more importantly, correlated with morphological data, circumscriptions will be redrawn and the number of Prunus species will be reduced[].

Common Name: Dwarf Russian Almond

General Information

Prunus tenella is a deciduous shrub with erect divaricate branches and rather numerous reduced branchlets; it can grow 80 - 150cm tall, occasionally to 200cm[, , ].
The plant is harvested from the wild for local use as a food. It can be used as a dwarfing rootstock and is also grown as an ornamental, where it can be used as a ground cover.
Although Prunus tenella is widespread, there is evidence of decline in its habitat in China because of habitat degradation due to frequent drought, fire regime change and over-grazing; some European populations are also threatened. There is a lack of information across the rest of the species' native range and so further research is recommended to determine population distribution, size and trend. The plant is classified as 'Data Deficient' in the IUCN Red List of Threatened Species(2013)[].

Known 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[]. 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[].
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[].

Botanical References

, ,

Range

Eurasia - Czech Republic, Austria and the Balkans, east to western Siberia, western China (Xinjiang) and Kazakhstan

Habitat

Dry grassland[]. Grasslands, valleys, hollows and dry slopes; at elevations up to 1,200 metres[]. Shrub steppes, growing in a range of soil types but particularly loess soil[].

Properties

Conservation Status	Data Deficient
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	0.80 m
Pollinators	Insects
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Prunus tenella is a very cold-tolerant species, when dormant it is hardy to about -25°c.
Requires a sunny position[]. Thrives in 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[]. The species prefers loamy soils but can grow in heavy clay; it grows best with soil pH 5.0 - 8.0[].
An attractive, early blossoming, ornamental, shrub[].
Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[]. This plant is a free-growing suckering shrub[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked. The fruit is quite variable in quality, the best forms are somewhat mealy with a fairly nice flavour[]. The whitish, straw yellow, ovate or orbicular -ovate fruit is about 10 - 25mm long and 12 - 20mm wide; it contains one large seed[, ].

Seed - raw or cooked. Kernels of the fruits are used to prepare bitter almond butter[]. Do not eat the seed if it is too bitter - see the notes above on toxicity.

Oil from the seed is used as an almond flavouring, it is inferior to the bitter almond oil obtained from Prunus dulcis[].

Medicinal

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[].

Agroforestry Uses:

Plants make a fairly good ground cover when spaced about 1 metre apart each way[].
Other uses of this species are as browse for wildlife, cover for game birds and rabbits, and as a small shrub for farmstead windbreak, riparian plantings and highway beautification[]

Other Uses

Used as a frost-resistant rootstock for the almond (Prunus dulcis)[].

This species is a secondary genetic relative of the Peach (Prunus persica) and Almond (Prunus dulcis), and so it has the potential for use as a gene donor for crop improvement. It has already been used in research into self-incompatibility and micropropagation[].

A green dye can be obtained from the leaves[].
A dark grey to green dye can be obtained from the fruit[].

The kernel contains bitter almond oil and is used for the production of an inferior almond oil as well as for bitter almond water which can be applied officinally instead of laurel cherry water[].

Propagation

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, mid summer in a frame[, ].
Softwood cuttings from strongly growing plants in spring to early summer in a frame[].
Layering in spring.
Division of suckers during the dormant season. They can be planted out direct into their permanent positions.