Tree Fruits – Plums

This document reviews the major plum cultivars recommended for Ontario in the Plum Cultivars – European and Japanese factsheet. In it, the term cultivar is any horticulturally recognized and named type or sort that can only be maintained through vegetative propagation or the use of selected breeding lines and seed sources.

Cultivars and requirements are described below.

Growth Climate Zones

Avoid areas where winter temperatures are severe enough to cause cold injury to shoots, fruit spurs, trunks and roots. Also, avoid areas where spring frost during bloom is a threat. Japanese plums are more susceptible to cold than European plums. Preference is to areas that have some moderating affect from one of the Great Lakes or on a site with a slope that allows for good air drainage.

Unfortunately, no hardiness zones are recommended so we will assume the same zones as for pears, zones 5b, 6a, 6b, 7a and 7b. Upper Canada Growers, the nursery that has the largest retail selection of fruit trees that we have found, recommends zones 5 and above. Depending on your site, choose the hardiest cultivars only. We will assume that the later the date of ripening, the farther away from spring frosts the cultivar may blossom.

In the factsheet Plum Cultivars – European and Japanese, Table 1 lists recommended varieties from earliest to latest dates of ripening. Table 2 lists most cultivars in order of the average dates of first commercial harvest at the University of Guelph, Department of Plant Agriculture, Vineland. Actual harvest dates and performance characteristics in any region may differ from dates above and general cultivar characteristic descriptions below.

Pollination Requirements

All recommended plum cultivars except Stanley, Bluefre and partially Italian, are self-unfruitful and require a cross-pollenizer variety with the same bloom date and annual blossoming. Refer to Table 3 of the factsheet for compatibility of European plum cultivars, and to Table 4 for compatibility of Japanese plum cultivars.

Honeybees, bumblebees and large flies are the major agents responsible for transferring pollen among plum cultivars. Like pears, plum blossoms have low sugar content (30%) and may suffer competition with flowers for pollenizing insects.

Following best management practices helps ensure the development of healthy trees that produce numerous, strong blossoms. Examples of best management practices are soil and air drainage (especially at bloom time), satisfactory soil fertility levels, appropriate pruning and integrated pest management (IPM) programs.

Cultivars

Below are cultivars from Table 1 referenced above. For pictures of fruit see the Plum Photo Gallery. Name colour code are: green for first choice due to the best characteristics of late maturity, fruit properties, and disease tolerance of trees; orange for second choice for trees that are slightly less than optimal but still excellent; and red for not recommended because of one or more severe limitations. Names uncoloured in black are considered undistinguished but may still be planted as good trees. Cultivar characteristics that have factored into the colour coding are shown in bold.

Cultivars  are:

European Plum Named Cultivars

  • Bluefre: (Shropshire): A fine-quality processing plum when properly mature. It is a self-fruitful, prolific cropper, producing small fruit that hang well on the tree. The flavour is very distinctive and is recommended for limited planting for specialty markets. It is reported to adapt well to mechanical harvesting.
  • Italian (Fellenberg): A medium-sized blue plum with good keeping and canning quality. It is less productive than Valor or Stanley. Italian and its sports are not recommended for planting in Ontario.
  • Stanley: A medium, dark blue, freestone fruit, oval in shape, with a fairly distinct neck. The flesh is yellow, juicy and of good quality. It is self-fruitful, productive and ripens a week earlier than Italian. In some years, it tends to overbear and will benefit from thinning.
  • ValerieTM (formerly V70031)A Valor x California Blue seedling. It is semi-freestone, medium to large sized violet-blue plum with good flavour. It is the first commercial European plum ripening about August 14 at Vineland. Self-unfruitful, it is pollinated by Stanley, Valor, Vanette, Veeblue, Verity, Victory, Vision and Voyageur.
  • Valor: A medium to large, violet-blue, semi-freestone plum of excellent quality. Valor ripens just ahead of Italian but is larger, much more productive and comes into bearing earlier than Italian. It is recommended as a fresh market cultivar.
  • VanetteTM (formerly V66071) An Early Rivers x Stanley seedling. This is a freestone, medium-large sized, ovate-shaped, purple-blue plum of good quality. It ripens about August 17 at Vineland, three days after Valerie. It is self-unfruitful, very productive and pollinated by Stanley, Valor, Veeblue, Verity, Victory, Vision and Voyageur.
  • VibrantTM NEW (formerly V70034) An early variety with a violet-blue skin and excellent bloom at maturity. The flesh is amber coloured and has a semi-freestone.
  • Victory: This large, attractive, heart-shaped, productive semi-freestone fruit is dark violet-blue with greenish, yellow flesh. It is firm, good quality and ripens five days after Stanley. It is recommended as a fresh market cultivar.
  • VioletteTM NEW: (formerly V72511) A mid-season variety with large oblong fruits. It has bluish-black skin with moderate bloom. The flesh is yellow-green coloured and has a semi-freestone. This variety is rich in total antioxidants.
  • Vision: This late-maturing plum is a large, oblong-shaped, dark blue freestone fruit of excellent quality. It ripens about October 1 at Vineland.

Japanese Plum Named Cultivars

  • Burbank: The seed producing the cultivar Burbank was received from Japan in 1883 by Luther Burbank, who made this selection, which the U.S. Department of Agriculture named after him in 1887. This good-quality plum is round, dark red, medium-sized, juicy, aromatic and clingstone. It ripens unevenly, beginning in late August at Vineland.
  • Early Golden: A round, golden, freestone plum with high red blush. It is firm and of good quality. While not as large as Shiro, the cultivar ripens 10-14 days earlier. Trees are very vigorous, outgrowing other plum cultivars. It has a biennial fruiting habit but can be eliminated with proper thinning and irrigation.
  • Ozark Premier A large, round, bright red, firm, aromatic clingstone of excellent quality. It ripens unevenly, in the same season as Burbank and Vanier.
  • Shiro: A round, yellow plum with a pink blush. It is very juicy, clingstone and fair in quality. It ripens 2 weeks after Early Golden.
  • VampireTM: NEW (formerly V82053) A late mid-season plum with medium-large fruits. It has an attractive blend of shiny green and ruby red skin. The flesh is red and very juicy. Exhibits more cold tolerance than any other red-fleshed plum here.
  • Vanier: A medium-sized, bright red clingstone with yellow flesh, maturing 2 weeks later than Shiro. The quality is good, firm, meaty and improves after fruit are picked and stored for 2-3 weeks. Trees are precocious, vigorous and have an upright growth habit. Best fruit quality is obtained through multiple picks.

Rootstock

Pear rootstocks belong to several species of pear (Pyrus) and a few are even in different genera (Cydonia, quince; Crataegus, hawthorn; Sorbus, mountain ash). In the past, Bartlett pear seedlings (Pyrus communis) have been used exclusively in Ontario as the standard rootstock for pear orchards.

Standard Rootstocks

  • Bartlett Seedling: produce vigorous trees and are adaptable to a wide range of soil and climatic conditions but they are all susceptible to fire blight.

Semi-dwarfing to semi-vigorous rootstocks

    • Old Home x Farmingdale Clones: are productive and do not show excessive suckering and are all highly resistant to fire blight and winter injury.
      • OHXF 40. Although it has only limited testing, early observations indicate that growth control with early production can be achieved.
      • OHXF 69. Trees from this rootstock may produce a tree approximately 70%-80% the size of a standard pear seedling. Reports from the west coast indicate that it may be somewhat susceptible to growing one-sided root systems.
      • OHXF 87. This rootstock is the highest producer of the Old Home series. It has demonstrated the ability to set fruit early and bear heavily. If allowed to crop heavy, it will give the grower a tree smaller than Bartlett Seedling.
      • OHXF 97 Is roughly the same size as Bartlett seedling trees but highly precocious. It is resistant to fire blight, pear decline, winter hardy and compatible with most cultivars.

Dwarfing rootstocks

Pear growers have been limited to Quince selections (Cydonia oblonga) for use as dwarfing rootstocks. Table 3, Graft compatibility of pear cultivars on Quince rootstocks, lists the pear cultivars, which are compatible and incompatible, when grafted directly on Quince.

Guidelines for orchard management of this rootstock are found in Pear Cultivars. Varieties used are:

  • Quince A. This rootstock is reasonably winter hardy (to -26° C.), tolerates excess soil moisture but not standing water, restricts vegetative growth of the pear scion cultivar, and induces fruit production at a younger age. It is not unusual to have fruit on 2 yr-old trees in the nursery or orchard.
  • Quince C. This is another clonal selection but has not proven to be as winter hardy as Quince A. It is more dwarfing than Quince A and very susceptible to leaf-spot fungus in the nursery.

This Series

References

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