Documentation of ancient plums growing in ancient times is scant. The best evidence for that earliest existence is best documented through America’s most famous pomologist, Luther Burbank, who reported in his twelve-volume botanical literary classic, Small Fruits, Volume IV, page 136, that the European plum, Prunus domestica, and its ancestor fruit originated in the Caucasus Mountains near the Caspian Sea. Burbank detailed evidence that the prune (dried plum) was a staple food of the Tatars, Mongols, Turks, and Huns “who maintained a crude horticulture from a very early period.” Various websites have presented the absurd idea that because the European plum, Prunus domestica, no seeds were found in the ruins of Pompeii after the eruption of Mount Vesuvius in AD 79, “while most other old world fruits were”, that this Plum could be concluded to be a recent “spontaneous chromosome” hybrid that duplicates itself to produce a hexaploid offspring.
The earliest reference to the history of plums in the American colonies comes from the Prince Nursery of Flushing, New York, which was established in 1737 and reported in 1771 in an advertisement for “33 Kinds of Plums” for sale. These plum trees were undoubtedly European plum trees, Prunus domestica.
After 1755, Henry Laurens, a guest and friend of Wililam Bartram, introduced olives, limes, ginger, evergreen strawberries, red raspberries, and blue grapes to the United States. From the south of France he introduced apples, pears, plums, and the white Chasselas grape, which bore abundant fruit. Henry Laurens lived in Charleston, South Carolina and served as President of the Continental Congress.
William Bartram described two species of American plums in his famous book, Travels, on his 1792 trip to Georgia, where he identified the Chicasaw plum, Prunus Chicasaw, and in Alabama found a wild plum, Prunus indica.
Luther Burbank contributed more to breeding and hybridizing plum trees of different species than any other person in history. His work on the stone fruit plum group is distinguished from anyone else by his unparalleled contribution to the improvement of various fruits grown and enjoyed today.
Burbank states that his importation of twelve plum seedlings in the year 1885 was the “largest importation of fruit trees ever made at a single time into the United States.”
Burbank brought in plums from around the world and interbred them in a giant “melting pot” to produce the best characteristics and reject the wrong ones. These plum genetic mixes were recombined over many generations, resulting in plum hybrids that are so different from the original species that they appear to be new species.
Burbank claimed that he spent more time hybridizing plums than any other breeding program, reporting that he evaluated 7.5 million crosses of hybrid plum seedlings before releasing outstanding cultivars for sale. His famous line of plum trees, which were popular in the late 1890s, are still admired and grown commercially for sale and in backyards today, including Burbank, Santa Rosa, Wickson, Golden, Satsuma, Shiro and Ozark. Premier. His first big success was applauded by USDA professor HE Van Deman, who suggested that Luther Burbank’s creation be named after its creator, thus “Burbank Plum.”
The most successful crosses between plums come from the most exotic Japanese plum, ‘Satsuma’, a name suggested by Professor HE Van Deman of the USDA, who identified it as imported from the Satsuma province of Japan. This unique plum developed a red skin with an overlay of pale blue mesh flowers. The pulp was deep purple red, firm, tasty and of excellent quality to be preferred for domestic use.
Burbank’s experimental species were the Japanese plums, Prunus triflora, which grew wild in Japan and were gathered by the natives. Japanese plums grew in many colors on the skin from white to purple, they were large and quite tasteless, but the native Japanese ate them while they were green and hard. Japanese plum genes seem to dominate most hybrid plum descendants. Chinese plums, Prunus simonii, were aromatic, with brightly colored skins, a small pit, but the skin cracks and the fruit tastes bitter.
European plums, Prunus domestica, range in size from large to small, sweet or tart, complex genes, many colored skins, highly adaptable, good to eat fresh, dried or canned. The downside: they are too juicy or watery. “Green Gage” is a well-known standard European cultivar. Plums are very high in sugar content.
Several species of American plums are very hardy and productive to the point of covering the ground in spring with several layers of fruit. These plums may be tasty but they have poor shipping quality. Burbank released an excellent hybrid strain from this cross called “Robinson plum”.
Several species of Native American plums have been used by Luther Burbank in hybridization experiments. American plums, Prunus americana, Scotch plums, Prunus hortulans, Chicasaw plum, Prunus augustifolia, Western sand plum, Prunus besseyi, Beach plum, Prunus maritima, and California wild plum, Prunus subcordata. These native plum trees are unusually cold hardy and cold temperatures do them no harm, even in the far north central United States.
The ‘Myrobalan’ plum originated as a French species, Prunus cerasifera is widely used as a peach and plum rootstock which tends to be compatible with the resulting fruit tree union and appears to be highly resistant to nematodes and root diseases.
Burbank’s goal in hybridizing plums was to produce a tree that had “stability, novelty, variety, hardiness, beauty, shipping quality, and adaptability.”
Plum leaves and twigs exhibit many subtle characteristics that the plant breeder can experiment with to predict the future characteristics of the fruit to be grown from small seedling crosses. Most hybridizers known from experience have a predictable result, although these plant qualities are too intangible to explain to an audience, such as changes in facial expressions or small variations in color changes. If the leaves of a plant are dark red, the fruit will be red. This same phenomenon is applicable to flowers such as the color of the canna lily leaf and the color of the red rhizome; or in crinum lily cultivars, a red bulb means a red flower; a light green bulb means a white flower.
Luther Burbank developed a seedless plum by hybridizing a French plum variety, “Sans noyaii”. These plums develop in various skin colors ranging from white to yellow, scarlet orange, crimson, violet, deep blue, almost black, striped, spotted and speckled. These seedless plums were delicious and unique, but they never found commercial success with growers or public demand.
Burbank crossed many plums that had a tendency to produce high-sugar fruit, like the sweetness of figs, pineapple, and oranges. This high sugar content makes it possible for the prune to ensure long-term preservation, when dried. The plum contains a thick, hard skin of such a texture that it is required not to crack when the commercial drying process begins and proceeds to deliver a tasty, honey-sweet fruit that lasts well.
A plum will not dry properly and become a marketable fruit unless the plum contains a sugar concentration of at least 15%. Before drying, the prune is briefly immersed in an alkaline solution that prevents future fermentation by preventing microbes from growing on the surface of the skin. For successful prune production commercially, a prune tree must be a reliable producer with a substantial annual crop of fruit. Prune must ripen early, when the days are long and warm, and must fall from the tree to avoid high harvest costs at the proper time of ripening. The prune should be cured and dry to a black color and develop a small pit. Most plum hybrids have been hybridized from the European plum, Prunus domestica.
There are also three varieties of ornamental plum blossoms that are recommended for planting: Newport Prunus cerasifera ‘Newport’, Purple Pony Prunus cerasifera ‘Purple Pony’ and Red Leaf Plum Prunus cerasifera ‘Thundercloud’ Plum Blossoms.
Burbank developed purple left plum trees from a purple-leaved French plum ancestor, Prunus pissardi, which are sold commercially as ‘Storm Cloud’, Vesuvius, and Othello plum blossoms. Some of these red-leaved flowering plums developed by Burbank produced luscious red fruit in addition to the beautiful ornamental red leaves.
Prune is high in antioxidant content that offers many health benefits such as vitamin A, vitamin B1, vitamin B2, vitamin C, niacin and minerals; Calcium, Potassium, Phosphorus and Iron.
Burbank evaluated the intricacies of plum hybridization and even crossed the plum with the almond, Prunus dulcis, in hopes of creating a tasty almond seed and flavorful pulp. He created many crosses with the apricot, Prunus armeniaca L., and created plum trees, a 50/50 mix of plum and apricot trees; The pluot trees demonstrate a 75/25 mix of plum and apricot trees; and Aprium trees, a 75/25 mix of apricot and plum trees.
Copyright (c) 2006 Patrick Malcolm
