Documentation on ancient plums growing in antiquity is scarce. The best evidence for that older existence is better 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 ancestral fruit originated in the Caucasus Mountains near the Caspian Sea. Burbank detailed the evidence that the prune (dried plum) was a staple food of the Tatars, Mongols, Turks and Huns “who maintained a raw horticulture from a very early period.” Various websites have proposed the absurd idea that because the seeds of the European plum, Prunus domestica, were not found in the ruins of Pompeii after the eruption of Mount Vesuvius in AD 79. C., “whereas most of the other fruits of the old world were”, this It could be concluded that the plum is a recent hybrid of duplication of a “spontaneous chromosome” to produce a hexaploid offspring.
The first reference to the history of plums in the American colonies came from the Prince Nursery of Flushing, New York, which was established in 1737 and reported in 1771 in a sales advertisement for “33 Kinds of Plums.” These plums were undoubtedly European plums, Prunus domestica.
After the year 1755, Henry Laurens, who was a guest and friend of Wililam Bartram, introduced olives, limes, ginger, strawberries, red raspberries, and blue grapes to the United States. From the south of France it introduced apples, pears, plums and the white Chasselas grape that gave abundance. 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, he found a wild plum, Prunus indica.
Luther Burbank contributed more to breeding and hybridizing plum trees of different species than anyone else in history. His work in the stone fruit plum group sets itself apart from anyone else for its unrivaled contribution to the improvement of various fruits that are grown and enjoyed today.
Burbank claims that its import of twelve plum seedlings in 1885 was “the largest import of fruit trees ever made in America.”
Burbank brought in plums from around the world and crisscrossed them in a giant “crucible” to produce the best characteristics and reject the wrong ones. These genetic mixtures of plums recombined over many generations and resulted in today’s plum hybrids that are so different from the original species that they appear to be new species.
Burbank stated that it spent more time hybridizing plums than with any other breeding program, and reported that it screened 7.5 million hybrid plum seedling crosses before releasing outstanding cultivars for sale. His famous line of plum trees that were popular in the late 1890s are still admired and grown commercially for sale and in backyard gardens today such as Burbank, Santa Rosa, Wickson, Golden, Satsuma, Shiro and Ozark Premier. Its first major success was applauded by USDA professor HE Van Deman, who suggested that Luther Burbank’s creation be named after its creator, hence “Burbank Plum.”
The most successful crosses between plums come from the Japanese plum, the most exotic, ‘Satsuma’, the name suggested by USDA Professor HE Van Deman, who identified it as imported from Japan’s Satsuma province. This unique plum grew a red skin with a layer of pale blue net flowers. The pulp was dark purplish red in color, firm, tasty and of excellent quality to be preferred for domestic use.
Burbank’s experimental species were Japanese plums, Prunus triflora, which grew wild in Japan and were pickled by natives. Japanese plums grew in many skin colors from white to purple, they were large and quite tasteless, but the Japanese natives ate them while they were green and hard. The genes of the Japanese plum appear to dominate most hybrid plum offspring. Chinese plums, Prunus simonii, were aromatic, with richly colored skins, a small pit, but the skin cracked and the fruit tasted bitter.
European plums, Prunus domestica, are of varied sizes, from largest to smallest, bittersweet, with complex genes, skin of many colors, very 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.
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 of this cross called “Robinson plum.”
Luther Burbank has used several species of Native American plums in hybridization experiments. American plums, Prunus americana, wild goose plums, Prunus hortulans, chicasaw plum, Prunus augustifolia, western sand plum, Prunus besseyi, beach plum, Prunus maritima, and California wild plum, Prunus subcordata. These native plums are unusually cold hardy and cold temperatures don’t hurt them, even in the northernmost part of the 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 union of the resulting fruit tree 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, strength, beauty, shipping quality, and adaptability.”
Plum leaves and twigs exhibit many subtle characteristics that the plant hybridizer may experience to predict future characteristics of the fruit to be grown from small seedling crosses. Most hybridizers know from experience a predictable outcome, even though these plant qualities are too intangible to explain to an audience, such as changing facial expressions or minor 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 variety of French plum, “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 mottled. These seedless plums were delicious and unique, but they were never commercially successful with growers or with public demand.
Burbank bred many plums that tended to produce high-sugar fruits, such as the sweetness of figs, pineapple, and oranges. This high sugar content makes it possible for the plum (prune) to ensure long-term preservation, when dried. The prune 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 produce 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 plum is briefly soaked in an alkaline solution that prevents future fermentation by preventing microbes from growing on the surface of the skin. For successful commercial pruning production, a pruning tree must be a reliable producer with a substantial annual fruit crop. Pruning should ripen early, when the days are long and warm, and it should fall from the tree to avoid costly harvesting costs at the proper time of maturation. The plum fruit should be cured and dried to a black color and a small pit grow. Most of the prune hybrids have been hybridized to the European plum, Prunus domestica.
There are also three ornamental varieties of flowering plum trees recommended for planting: Newport, Prunus cerasifera ‘Newport’, Purple Pony Prunus cerasifera ‘Purple Pony’, and Red Leaf Plum Prunus cerasifera ‘Thundercloud’, flowering plums.
Burbank developed purple-leaved plums from an ancestor of French plums with purple leaves, Prunus pissardi, which are sold commercially as “Storm Cloud” flowering plums, Vesuvius, and Othello. Some of these Burbank-developed red-leaved flower plums produced delicious red berries in addition to the beautiful red ornamental leaves.
The plum is high in antioxidants that offers many health benefits such as vitamin A, vitamin B1, vitamin B2, vitamin C, niacin and the minerals; Calcium, Potassium, Phosphorus and Iron.
Burbank examined the intricacies of hybridizing the plum and even crossed the plum with the almond, Prunus dulcis, in hopes of creating a flavorful almond kernel and flavorful pulp. He created many crosses with the apricot, Prunus armeniaca L., and created plumcot trees, a 50/50 mix of plum and apricot trees; Pluot trees show a 75/25 mix of plum and apricot; and Aprium trees a 75/25 mix of apricot and plum trees.
Copyright (c) 2006 Patrick Malcolm
