Plums are a remarkably diverse group, comprising several different species and sub-groups which are often difficult to distinguish one from the other. Some of the major plum groupings are described here.
Prunus domestica - European plum
This is the European plum, widely-planted in Europe and without doubt one of the most flavoursome fruits that can be grown in temperate climates. They come in a range of attractive colours, from yellow to pink to purple. The flesh is almost invariably a golden yellow - this is a good way to distinguish them from Japanese plums. Although perhaps not quite as popular as apples, they make ideal garden trees, usually requiring less attention than apple or pear trees.
Whilst European plums do not store particularly well, the fruit usually ripens over a 1-2 week period, during which time the tree can be picked daily to ensure a steady supply of fruit.
European plums are grown commercially on a small scale in the UK, France, and Germany and are available in European supermarkets for a short period in the summer. They are also grown in the USA where they are mostly used for canning and preserving.
Prunus domestica is not indigenous in Europe, and is thought to be a natural hybrid of the cherry plum and the sloe which were introduced to Europe from the Middle East.
European plum trees are easy to grow in most climates - see our plum trees for sale.
Prunus domestica - Gages
Although now usually included within Prunus domestica, it is convenient to consider the Gages as a sub-group of European plums because of their interesting and sophisticated flavours.
Gage trees and flowering times are similar to the mainstream European plums. Gages tend to be either green or golden/yellow in colour, with pale green or pale yellow flesh. The green gages are easier to distinguish being invariably smaller and rounder than regular European plums. Yellow gages are usually larger and look more like plums.
Gages prefer slightly warmer growing conditions than other European plums to bring out their full flavour, and their natural home is France where have been cultivated since the Middle Ages having been introduced from Italy. In France the many different varieties of green-skinned gages are known collectively as "Reine Claude" in honour of Queen Claude, the wife of Francis I who ruled France from 1515 to 1547 when these plums first became popular. The term Reine Claude, as in for example, Reine Claude de Bavay, means a gage plum.
Gages are named after Sir William Gage, an Englishman who popularised one of these varieties in England in the 18th century - and named it after himself. Gages were subsequently introduced to the USA in the late 18th century.
There is a further distinct sub-group within the Gages known as the transparent or diaphanous gages. These fruits have a translucent skin and if held up to the light the outline of the stone can be seen inside. The most well-known are Early Transparent Gage and Golden Transparent Gage.
Gages have a distinctive rich sweet flavour, sometimes considered the most refined of any temperate fruit.
Prunus salicina - Japanese plum
This is the plum that you are most likely to find year-round in supermarkets, with large-scale production in California (where almost all of the USA's production is centred) as well as China, Chile, and the warmer areas of Europe. The fruit has a longer shelf-life than European plums, and is better-suited to being transported around the world. However the flavours are generally less interesting than in European plums, and the fruit is less versatile, being almost exclusively for eating fresh.
Japanese plums are usually not self-fertile (whereas many European plums are self-fertile). Japanese plums and European plums will not cross-pollinate each other, partly because their flowering periods do not overlap.
The plums are usually round, and either golden yellow or dark red in colour. The flesh is usually dark red in the red-coloured varieties, which is a good way to distinguish them from European plums which invariably have yellow or green flesh. Japanese plums prefer a warm dry climate, and may flower too early to be grown successfully in cool temperate climates.
Prunus salicina actually originates from China, but was introduced to the rest of the world via Japan and then California - the term "Japanese plum" is therefore something of a misnomer. The species is sometimes also called Prunus triflora because it produces flowers in sets of three (hence triflora) instead of in pairs like Prunus domestica. One useful consequence of this is that trees of Prunus salicina trees are often more productive than Prunus domestica because they produce more blossom and can set more fruit.
Several plum-related inter-species hybrids have been developed using Japanese plums, e.g. Pluots which are typically 3/4 Prunus salicina and 1/4 Prunus armeniaca (apricot).
This is a diverse group of lesser plum species, but closely related to the European plum. Most of them have good disease resistance, and will cross-pollinate with European plums with similar flowering times.
Damsons originate from Damascus in Syria and the name comes from the term "Damascene plum". They are primarily used for cooking, although they can be eaten fresh when fully ripe. Damsons are small round or spherical fruits, nearly always blue-black in colour. They have a rich spicy and very attractive astringent flavour when cooked, which is quite distinctive. Damsons will cross-pollinate with other European plum varieties, and are usually self-fertile.
Perhaps surprisingly given their origins in the Middle East, Damsons are very well adapted to maritime climates and in the UK the centre of commercial damson production is the Lyth valley in Cumbria, north-west England, notable for its mild wet climate.
Bullaces are essentially small damsons, often with a rounder shape, and used for similar purposes.
Mirabelles are grown particularly in north-east France. The fruits are very small, the size of large cherries, and typically either bright red or golden yellow. Mirabelles can be eaten fresh, but are primarily used for making jams and similar preserves, as well as fruit tarts ("tarte aux mirabelles"). They are also the variety most often used in plum brandy and similar plum-based spirits. Mirabelles are closely related to Damsons but the fruit is much sweeter.
Mirabelle trees are hardy and grow well throughout Europe and North America. They flower at around the same time as mainstream European plums, with which they will readily cross-pollinate. The fruit ripens in mid or late summer - much later than Cherry Plums with which they are sometimes confused. A characteristic of Mirabelles is that they are usually partially self-fertile.
Saint Juliens are small rounded fruits, usually a pale green colour. They used to be used for drying, but nowadays Saint Juliens are most commonly used as a rootstock for many other Prunus varieties. The reason is that Saint Juliens produce naturally smaller trees than other plum varieties, a desirable characteristic for commercial orchards and gardens, yet are widely-compatible with them. In essence, you can graft a flavoursome Prunus domestica variety on to a Saint Julien rootstock, and you have the same fruit but on a smaller tree, which starts producing crops within only 3-4 years.
Prunus cerasifera - Cherry Plum
Cherry plums are closely related to the European plum (more so than to the true cherry). The most commonly-found varieties are tomato-red or bright yellow in colour but they can also be green or almost black.
The fruits are similar in size to Mirabelles, with which they are easily confused. However Cherry Plums are reliably self-fertile whereas Mirabelles are usually only partially self-fertile. Cherry plums also flower much earlier in the spring, and the fruit ripens in early summer, well before mirabelles.
Traditional Cherry Plums are sometimes known as Myrobalan plums, and can be used as rootstocks for many European plum varieties.
The modern cherry plum varieties available in garden centres are often a bit larger than the traditional varieties, and might have some relation to the Japanese plum (Prunus salicina).
Prunus spinosa - Sloe
Sloes are very small blue-black fruits, rather like small Bullaces. They are common in northern European hedgerows, and are believed to be part of the ancestry of the European plum. It is traditional to wait until the fruits have been tenderised by a good frost before picking, and they are commonly used for making fruit spirits.
Other Prunus species
Although not considered further in this article, the following popular fruits are all related to plums:
Prunus armeniaca - Apricots.
Prunus persica - Peaches and Nectarines.
Prunus avium - Sweet cherry.
Prunus cerasus - Acid or Tart or Sour cherry.
Prunus dulcis - Almond. It may seem surprising at first that plums and almonds are related, but almonds are in essence a type of plum where the nut (inside the stone) rather than the flesh is eaten. The characteristic flavour of almonds can also sometimes be detected in cooked European plums, particularly the popular English Victoria plum.
We would like to thank Hamid Habibi of Keepers Nursery for advice on this article.