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Rosaceae FAMILY

Pyrus calleryana

Pyrus calleryana

Edibility
2/5
Medicinal
0/5

Safety & Hazards

The pollen can be bothersome to people with allergies[1]. Although no specific information has been seen for this plant, the seed of many species in the family Rosaceae are likely to contain cyanogenic glycosides. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[2]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted. In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[3]. The levels of toxin can be detected by the level of bitterness:- sweet almonds, for example, contain only very low levels of it and are safe to eat in quantity, whilst bitter almonds (which are used as a flavouring in foods such as marzipan) contain much higher levels and should only be eaten in very small quantities. Great caution should be employed if the taste is moderately to very bitter[PFAF].

Cultivation Details

HabitDeciduous Tree
GrowthMedium

Pyrus calleryana is a very cold-hardy plant, tolerating temperatures down to around -40°c when dormant[4, 5]. Prefers a good well-drained loam in full sun[5]. Grows well in heavy clay soils. Tolerates light shade but does not fruit so well in such a position. Tolerates atmospheric pollution, excessive moisture and a range of soil types if they are moderately fertile[5]. Established plants are drought tolerant[5]. Grows well on acid soils[4]. There are many named forms selected for their ornamental value[5]. The cultivar 'Bradford' is a dense, vigorous tree that is resistant to fireblight, though it has a tendency to split in snow or high winds[6, 7, 8]. Plants are moderate to fast growing[9]. Resists fireblight, collar rot, root aphis, pear psylla and root lesion nematodes[4]. This species is resistant to most important diseases and pests. For this reason, several different cultivars had been selected as street trees[10].. Trees have a short dormancy period and lose their leaves late in the season[4].

Propagation

Seed - best sown in a cold frame as soon as it is ripe in the autumn, it will then usually germinate in mid to late winter. Stored seed requires 8 - 10 weeks cold stratification at 1°c and should be sown as early in the year as possible[5]. Temperatures over 15 - 20°c induce a secondary dormancy in the seed[5]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in a cold frame or greenhouse for their first year. Plant them out in late spring or early summer of the following year. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Pyrus+calleryana>

Pollinators

Insects

References

  1. [1]Flowers of India — http://www.flowersofindia.net/ ↩︎A wed site of native Indian plants, plus cultivated and naturalized species. It has good quality photos and terse details on more than 3,000 species and cultivars.
  2. [2]Encyclopaedia of Herbs and their Uses. — Bown. D. · Dorling Kindersley, London. · 1995 · ISBN 0-7513-020-31 ↩︎A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.
  3. [3]Poisonous Plants of North Carolina — http://www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm ↩︎An excellent concise but comprehensive guide to toxic plants that grow in N. Carolina. It lists even those plants that are of very low toxicity, including several well-known food plants such as carrots and potatoes.
  4. [4]Wonder Crops. 1987. — Natural Food Institute, ↩︎Fascinating reading, this is an annual publication. Some reports do seem somewhat exaggerated though.
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]The RHS Gardener's Encyclopedia of Plants and Flowers — Brickell. C. · Dorling Kindersley Publishers Ltd. · 1990 · ISBN 0-86318-386-7 ↩︎Excellent range of photographs, some cultivation details but very little information on plant uses.
  7. [7]Global Invasive Species Database — http://www.issg.org/database/welcome/ ↩︎Very detailed information on almost 400 species (with more being added) of plants that have become weeds in areas outside their native range.
  8. [8]New Trees — Grimshaw J.; Bayton R.; Wilks H. · Kew Publishing; London · 2009 · ISBN 1842461737 ↩︎Provides comprehensive botanical descriptions and horticultural commentary on over 800 tree species that have been introduced to cultivation in recent decades.
  9. [9]Southern Trees Fact Sheets — Gilman E.F. · University of Florida, IFAS Extension · http://edis.ifas.ufl.edu/department_envhort-trees ↩︎A series of fact sheets on trees that can be grown in Florida. They can be downloaded from the Internet
  10. [10]Mansfeld's Database of Agricultural and Horticultural Plants — http://mansfeld.ipk-gatersleben.de/pls/htmldb_pgrc/f?p=185:3:4292127278597336 ↩︎Terse details of a huge range of useful plants.
  11. [11]Flora of China — Missouri Botanical Garden Press; St. Louis. · 1994 · http://flora.huh.harvard.edu/china/ ↩︎An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
  12. [12]Plantae Wilsonae. Vol 1 - 3 — Wilson. E. H. · University Press; Cambridge. · 1911 - 1917 · http://www.biodiversitylibrary.org ↩︎Details of the palnts collected by the plant collector E. H. Wilson on his travels in China. Gives some habitats. Not for the casual reader. It can be downloaded from the internet.
  13. [13]Tanaka's Cyclopedia of Edible Plants of the World. — Tanaka. T. & Nakao S. · Keigaku Publishing; Tokyo · 1976 · ISBN - ↩︎The most comprehensive list of edible plants I've come across. Only the briefest entry for each species, though, and some of the entries are more than a little dubious. Not for the casual reader.
  14. [14]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
  15. [15]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  16. [PFAF]Plants for a Future — pfaf.org ↩︎