Tree Fruits – Pears

Opened on March 03, 2021. Last updated by The POOG on March 09, 2021.

Growth Climate Zones

Pears are recommended for production in Zones 5b to 7b. See Figure 1 below for an Ontario zone map.    

Figure 1. Plant Hardiness zones for Ontario.

Pollination Requirements

Under Ontario conditions, commercial pear cultivars are considered self-unfruitful; consequently, cross-pollination with a suitable pollenizer cultivar is required. Most recommended pear cultivars flower at the same time and there is often satisfactory bloom overlap. The nectar of pear flowers contains about 10% sugar making for low attraction to pollinators.

Anjou and Flemish Beauty are good pollenizers for Bartlett and Bosc. Bartlett and Seckel are cross-incompatible. Bartlett and Bosc are satisfactory pollenizers of each other, as well as of other cultivars. Flemish Beauty has shown the highest degree of self-fertility.

See the factsheet for further cross-pollination arrangements and planting patterns.

Cultivars

Pears have a wide range of harvest dates from Aug. 6 for Gifford to Oct. 7 for Bosc (see Table 2, Average date of first harvest for pear cultivars).

Below are cultivars from Table 1, Recommended Pear Cultivars. Name colour codes are: green (#3fd200) for first choice due to the best characteristics of late maturity, fruit properties, and disease tolerance of trees; orange (#d2a400) for second choice for trees that are slightly less than optimal but still excellent; and red (#ff0000) 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:

  1. Anjou. When well grown and properly handled, Anjou is a good quality dessert pear of long storage and shipping life. The skin is light green and, unlike Bartlett, does not change from green to yellow upon maturity. The flesh is very mild, aromatic and fine-textured. Lack of fruit-set is a common weakness of this cultivar. The tree is more fire blight resistant than the Bartlett cultivar. Anjou pear plantings in Ontario have decreased considerably since 1990 because the fruit’s size and appearance has been only fair and has difficulty competing with other larger, cleaner pears.
  2. Bartlett. This cultivar comprises about 75% of total pear production in North America. In Ontario, it is the leading cultivar by hectares and number of trees. Bartlett trees are productive and adaptable to a wide range of soils and climatic conditions. Careful orchard management is required to avoid fire blight and still obtain satisfactory yield and quality. Pick fruit at a pressure of 6.8-8.0 kg (15-19 lb) as measured on a pared surface of the fruit using a pressure tester with an 8 mm diameter tip plunger. Store fruit immediatelyat 1° C (30° F) until a week before it is used. Rapid removal of field heat and prompt cooling of harvested pears are associated with successful long-term storage. The maximum storage period for Bartlett at -1° C is about 2½-3 months. In some years, abnormally cool temperatures 4-5 weeks prior to harvest have stimulated premature ripening of Bartlett pear. These pears soften, become yellow, and ripen at an accelerated rate. Do not store for a long period. Ripen Bartlett fruit at temperatures from 15-21° C (60-70° F). Maintain relative humidity in the storage and ripening rooms at about 90-95%. Swiss Bartlett is a strain of Bartlett, which has similar tree and fruit characteristics. A red budsport of Bartlett known as Max-Red Bartlett is also available. Max-Red is similar to Bartlett except for its red colour. It ripens one week after Bartlett.
  3. Bosc. A high quality, flavourful, dessert winter pear with excellent keeping and shipping quality. Bosc is widely grown as a dessert pear in the western U.S. It is an important and well-adapted pear in milder regions of Ontario. The trees are very productive, come into bearing late and are susceptible to fire blight. They are difficult to train due to their leggy growth habit and lack of branching. A strain of Bosc from Oregon called OP-5 appears promising and warrants testing by growers in Ontario. In tests at Vineland, this strain has produced at an earlier age, and has an improved fruit shape and more uniform brown colour.
  4. Clapp’s Favorite. An attractive, large, productive, good quality pear maturing 2 weeks ahead of Bartlett. Pick fruit when they attain sufficient size, at least 10 days before full maturity. Failure to harvest fruit at the proper stage of maturity results in rapid core breakdown. The tree is vigorous, bears early and regularly, does well on heavy soils and is very cold hardy. It is susceptible to fire blight, however. Starkrimson is a brilliant solid red budsport of Clapp’s. It has slightly tougher skin but is otherwise identical.
  5. Flemish Beauty. The hardiest cultivar available for colder districts of Ontario. Flemish Beauty is susceptible to scale and fire blight. The tree is very productive and vigorous. The fruit are high in quality, but require careful timing of harvest to obtain full flavour and freedom from breakdown.
  6. French Bartlett (Doctor Jules Guyot). An old cultivar that was introduced to North America around 1885. Guyot resembles Bartlett in shape and colour, but tends to be larger and rougher. Trees come into bearing early, but breakage of branches is sometimes a problem. Guyot is not as good in quality as Bartlett but is quite acceptable. It ripens with or just after Clapp’s Favorite.
  7. Giffard. An early summer pear of good quality and medium size. When picked at the correct stage of maturity, it keeps well. It is suitable only for limited commercial planting as an early roadside and farm market cultivar.
  8. AC™ Harrow Crisp (formerly HW 610) (Parentage: Bartlett x US56112-146). It is a very attractive pear with red blush on smooth yellow skin. The cream-white flesh is smooth, grit-free and firm even when fully ripe, with a mild sweet flavour. The fruit matures at the end of Aug. or early Sept., about the same time as Bartlett. It can be picked over a 2-week period. Early picked fruit can be stored for about 2 months, but storage life is reduced with later picking. If kept too long or picked too late, it will deteriorate internally without external signs. Fruit size on unthinned trees is slightly larger than Bartlett. It has a good to very good rating for fresh fruit quality. When processed as pear halves, it has maintained its integrity, received good to very good ratings, and has been included in a CanAdapt pear trial. The tree is medium in size, conical and upright, annually productive and hardy. It is a poor pollenizer. The tree has excellent resistance to natural fire blight infections (9.5 rating compared to Bartlett reading of 4.2), similar to Harrow Sweet and Harvest Queen. Following inoculation, lesion development may extend to about 15% of current season’s growth. Precocity of AC™ Harrow Crisp is similar to Bartlett, trees coming into production about 4 years after planting. AC™Harrow Crisp is protected under the Plant Breeders Rights Act (application number 00-2184).
  9. AC™ Harrow Gold (formerly HW 616) (Parentage: Harvest Queen x Harrow Delight). Fruit are picked about 10 days before Bartlett, between Harrow Delight and Harvest Queen. An attractive yellow fruit, with good size (larger than Harvest Queen, similar in size to Bartlett), smooth skin, fine texture, very good flavour with a good balance between sweetness and acidity, and exceptionally juicy. The fresh fruit quality of AC™ Harrow Gold is rated similar to Bartlett. As with many other early season pears, the fruit will not store for very long (probably no more than 4-6 weeks) in common cold storage, but it is excellent for roadside stands. This cultivar has received good to very good processing ratings and has been included in the CanAdapt pear trial. AC™ Harrow Gold has excellent resistance to natural fire blight infections (9.6 rating); however, in some years following inoculation with the causative organism, lesions have developed which have extended to about 25% of current season’s growth. Precocity in a second test planting appears to be similar to that of Bartlett. AC™ Harrow Gold is protected under the Plant Breeders Rights Act (application number 00-2185).
  10. Harrow Delight. The fruit, smaller than Bartlett, are greenish yellow in colour with a red blush. The cultivar ripens 2 weeks before Bartlett and is resistant to fire blight. Pick fruit while still green; otherwise, it drops heavily. Harrow Delight is pollen-compatible with Bartlett, Bosc, Anjou and Harvest Queen.
  11. Harvest Queen. The fruit resemble Bartlett in shape, colour, texture and flavour, but are smaller than Bartlett. Thinning will improve fruit size and reduce the tendency toward biennial bearing. Harvest Queen ripens 1 week before Bartlett and is as resistant to fire blight as Kieffer. Fruit hangs well on the tree and size will improve with delayed picking. Harvest Queen is pollen-compatible with Bosc, Anjou and Harrow Delight, but not Bartlett.
  12. Harrow Sweet™ (PBR #0572). Fruit size is comparable to Bartlett, colour is yellow with a red blush at maturity, and taste is sweet, juicy and excellent. The cultivar ripens 3½ weeks later than Bartlett and trees show good resistance to fire blight. Harrow Sweet is reciprocally pollen-compatible with Bartlett.
  13. Kieffer. Strictly a canning pear of poor quality and a poor pollenizer for major pear cultivars grown in the province. Although it is highly fireblight resistant, most Kieffer plantings have been removed and planting Kieffer is not advised in Ontario.
  14. Seckel. A very high-quality, attractive, productive, small, late pear. The core tends to break down in the middle near harvest. In Ontario it has been used for pickling. Seckel should be planted only in home gardens and for special markets in Ontario.

Rootstock

Standard Rootstocks

Bartlett Seedling. At the present time most of the pear trees in North America are grown on seedlings of Bartlett. These seedlings produce vigorous trees and are adaptable to a wide range of soil and climatic conditions but they are all susceptible to fire blight in the nursery and orchard. Trees of Bartlett on Bartlett seedling rootstock are moderately vigorous and strong. The root system is composed of numerous, roots that are well distributed for anchorage. The fruit tend to be medium in size, fairly well shaped and high in soluble solids.Bartlett seedling is still the main recommended rootstock for pear in Ontario.

Semi-dwarfing to semi-vigorous rootstocks

Old Home x Farmingdale Clones
The clonal selections OHxF 40, 69, 87 and 97 have been classified as semi-dwarfing in vigour compared to trees with standard rootstock and are under evaluation in a CanAdapt demonstration trial at various climatic locations in Ontario. Trees on these OHxF clones are productive and do not show excessive suckering. These clones propagate readily from hardwood cuttings and are all highly resistant to fire blight and winter injury. OHxF clones have been tested at the Mid-Columbia Agriculture Research and Extension Center in Hood River, Oregon.
Past trials at AAFC, Harrow with Harvest Queen indicate OHxF 69 and 87 are promising rootstocks while OHxF 333 produced a smaller tree but reduced fruit size.
The following OHxF clones are under test and have been included in the CanAdapt pear trial.

  • 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

For size controlling rootstocks, pruning and training systems need to be amended in order ensure the size controlling effect. 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.

  • 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. Since the standard Bartlett is incompatible on Quince, Swiss Bartlett, a strain of Bartlett, which is compatible with Quince A, is used directly on Quince roots. Bosc is also incompatible with Quince A. The cultivars Anjou, Duchess and Hardy are recommended for use as a graft compatible interstem. In research trials, Bosc with Old Home interstem has produced lower yields and smaller fruit. Trees of Bosc on Quince rootstocks are about the same size with all the interstems mentioned above.
  • 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. Quince C is presently under evaluation at Vineland.

References

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