The early colonists found plums growing wild along the entire Eastern coast. They were one of many fruits eaten by the Indians before the coming of the white man, and reports of early explorers mention the finding of plums growing in abundance. Today however native plums are not important commercially. The European type of plums, Prunas Domestica, has replaced the native plum. Plum pits from Europe probably were brought to America by the first colonists, for it is reported that plums were planted by the Pilgrims in Massachusetts, and the French brought them to Canada.
Although plums came to America by way of Europe, they are believed to have originated in Western Asia in the region south of the Caucasus Mountains to the Caspian Sea. According to the earliest writings in which the European plum is mentioned, the species dates back at least 2000 years.
Another species, Prunus Institia, known to us as the Damson plum, also came to America by way of Europe. This plum was named for Damascus and apparently antedates the European type, although Damson pits have been found in the lake dwellings of Switzerland and in other ancient ruins.
Another important species, the Japanese plum, was domesticated in Japan, but originated in China. It was introduced in the United States about 1870. This type is grown extensively in California.
Plums have been grown in some of the Spanish mission gardens of California at least as early as 1792, and the first prune plums grown in California were produced in Santa Clara Mission. However, the present California prune industry is not based on these but the French prune, Petite Prune d’Agen, scions of which were brought to California from France in 1856 by Pierre Pellier. French-type prunes grown in California orchards were shipped in to San Francisco markets in 1859.
Botanically, plums and prunes of the European or Domestica type belong to the same species. The interchangeable use of the terms plum and prune dates back for several centuries. Plum is Anglo-Saxon, and prune is French. It is uncertain just when the word prune was first used to designate a dried plum or a plum suitable for drying. The prune is a variety of plum that can be dried without fermenting when the pit is left in. Fresh prunes, as compared with plums, have firmer flesh, higher sugar content, and frequently higher acid content. A ripe, fresh prune can be separated from the pit like a freestone peach, but a plum cannot be opened this way.
Of all the stone fruits, plums have the largest number and greatest diversity of kinds and species. H.F. Tysser, editor of Fruit Manual, published in London, says there are over 2000 varieties. Samual Fraser, in his book America Fruits, speaks of a list of about 1500 varieties of Old World plums alone, and says there probably are just as many varieties of plums native to this continent. In addition, there is a long list of Japanese and Chinese plums.
Almost all of the plums shipped in the United States are grown in California. There are two types of California plums, Japanese and European. The former marketed early in the season and the latter in midseason or later. The Japanese varieties are characterized by their large size, heart-shape, and bright red or yellow color. Japanese varieties are never blue.
Plums and prunes of good quality are plump, clean, of fresh appearance, full colored for the particular variety, and soft enough to yield to slight pressure. Unless one is well acquainted with varieties, color alone cannot be replied upon an indication of ripeness. Some varieties are fully ripe when the color is yellowish-green, others when the color is red, and others when purplish-blue or black. Softening at the tip is a good indication of maturity. Immature fruit is hard. It may be shriveled and is generally of poor color or flavor. Over mature fruit is generally soft, easily bruised, and is often leaky.
Fresh plums are more acid to the body than fresh prunes. When too many plums are eaten, an over acid condition results. When prunes are dried, however they are wonderful for the nerves because the contain a phosphorus content of nearly 5 percent.
Prunes have a laxative effect. The dried prune is better to eat than the fresh plum or prune. The salts contained in the dried prune are valuable as food for the blood, brain and nerves. The French prunes are considered the best for their value to the nervous system.
NUTRIENTS IN ONE POUND
Protein: 3 g
Fat: 0.9 g
Carbohydrates: 55.6 g
Calcium: 73 mg
Phosphorus: 86 mg
Iron: 2.2 mg
Vitamin A: 1200 I.U.
Thiamine: 0.28 mg
Riboflavin: 0.18 mg
Niacin: 2.1 mg
Ascorbic acid: 20 mg