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Juglandaceae FAMILY Least Concern

Carya illinoinensis

Carya illinoinensis

Edibility
4/5
Medicinal
2/5

Safety & Hazards

None known

Cultivation Details

HabitDeciduous Tree
GrowthMedium

Carya illinoinensis grows in a humid climate; the minimum average annual rainfall approximates 760mm and the maximum reaches 2,010mm, of which at least 510mm falls during the growing season. Annual snowfall varies from zero to 50cm. Mean summer temperatures range as high as 27°c, with extremes of 41 - 46°c. Average winter temperatures vary from 10° to -1°c, with extremes from minus 18° to plus 29°c[1]. Dormant trees are said to be hardy to about -12°c, the same report also says that they are hardy to zone 5[2], which would experience considerably lower temperatures than this. Trees are probably much hardier when grown in areas with hot summers. In the wild, trees grow best in areas where summer temperatures average 24 - 30°c and the humidity is high[3]. Prefers a deep moisture-retentive loam in a sunny sheltered position, requiring a good summer for best development[4, 5, 6, 2]. The wild plant grows on rich, well drained, alluvial soils often near river bottoms but not in localities experiencing prolonged flooding[7]. Tolerates a pH in the range 4.5 to 8.3. Trees are fairly fast growing[2]. Trees do not grow very well in cool maritime climates, requiring hotter summers than are normally experienced in order to fruit and fully ripen their wood[2]. However, a tree at Cambridge botanical gardens was 20 metres tall in 1985. Often cultivated for its edible seed, there are some named varieties[8]. Trees come into bearing when about 20 years old, the best period of production being between the ages of 75 to 225 years old[3]. Mature trees regularly give yields of 225 kilos, whilst yields of 450 kilos have been recorded[3]. A number of cultivars have been developed in N. America that succeed quite far north in that country[2]. These cultivars include:- 'Carlson 3'. Early maturing, it is being trialled in Canada[8]. 'Devore'. An early fruiting form with small nuts that have an excellent flavour[8]. 'Gibson'. Precocious, protandrous, the nuts are of medium size with a good flavour[8]. 'Green Island'. Amongst the hardiest of cultivars, it has been selected for nut size, flavour and productivity[8]. 'Mullahy'. Hardy, precocious and very productive, it has ripened in Ontario[8]. Nuts are fairly large with an excellent flavour. 'Voiles 2'. Usually ripens as far north as Ontario and New York[8]. The wind-blown pollen is a significant cause of hay fever in the Unitd States[9]. This species is the State Tree of Texas[9]. Plants are strongly tap-rooted and should be planted in their permanent positions as soon as possible[4, 6]. Sowing in situ would be the best method so long as the seed could be protected from mice[4, 2]. Plants in this genus are notably resistant to honey fungus[2]. Most species in this genus have quite a wide range of distribution and, in order to find trees more suited to this country, seed from the most appropriate provenances should be sought[6]. Most trees growing in Britain at present tend to only produce good seed after hot summers[6]. Trees are self-fertile but larger crops of better quality seeds are produced if cross-pollination takes place[3].

Propagation

Seed - requires a period of cold stratification. It is best sown in a cold frame as soon as it is ripe[10]. Stored seed should be kept moist (but not wet) prior to sowing and should be sown in a cold frame as soon as possible[10]. Where possible, sow 1 or 2 seeds only in each deep pot and thin to the best seedling. If you need to transplant the seedlings, then do this as soon as they are large enough to handle, once more using deep pots to accommodate the tap root. Put the plants into their permanent positions as soon as possible, preferably in their first summer, and give them some protection from the cold for at least the first winter[10, PFAF]. Seed can also be sown in situ so long as protection is given from mice etc and the seed is given some protection from cold[2] (a plastic bottle with the top and bottom removed and a wire mesh top fitted to keep the mice out is ideal) Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Carya+illinoinensis>

Pollinators

wind

References

  1. [1]Silvics of North America. Agricultural Handbook No. 654. — Burns. R.M. & Honkala. B.H. · USDA Forest Service; Washington DC. · 1990 · http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm ↩︎A very comprehensice guide to about 200 species of timber trees of N. America, Hawaii and Puerto Rico. Mainly temperate species, plus a number of tropical species. It is downloadable from the Internet.
  2. [2]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.
  3. [3]The Complete Trees of N. America. Field Guide and Natural History. — Elias. T. · Van Nostrand Reinhold Co. · 1980 · ISBN 0442238622 ↩︎A very good concise guide. Gives habitats, good descriptions, maps showing distribution and a few of the uses. It also includes the many shrubs that occasionally reach tree proportions.
  4. [4]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  5. [5]Nuts. — Howes. F. N. · Faber · 1948 · ISBN - ↩︎Rather old but still a masterpiece. Has sections on tropical and temperate plants with edible nuts plus a section on nut plants in Britain. Very readable.
  6. [6]The Plantsman. Vol. 9. 1986 - 1987. — ? · Royal Horticultural Society · 1986 · ISBN - ↩︎Excerpts from the periodical giving cultivation details and other notes on some of the useful plants including Carya spp and Crocus sativus.
  7. [7]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
  8. [8]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.
  9. [9]Illustrated Flora of North Central Texas — Diggs, Jnr. G.M.; Lipscomb. B. L. & O'Kennon. R. J · Botanical Research Institute, Texas. · 1999 · http://artemis.austincollege.edu/acad/bio/gdiggs/NCTXpdf.htm · ISBN 1-889878-01-4 ↩︎An excellent flora, which is also available on-line.
  10. [10]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  11. [11]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.
  12. [12]An Illustrated Flora of the Northern United States and Canada — Britton. N. L. Brown. A. · Dover Publications. New York. · 1970 · ISBN 0-486-22642-5 ↩︎Reprint of a 1913 Flora, but still a very useful book.
  13. [13]Dictionary of Economic Plants. — Uphof. J. C. Th. · Weinheim · 1959 · ISBN - ↩︎An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.
  14. [14]Manual of the Trees of N. America. — Sargent. C. S. · Dover Publications Inc. New York. · 1965 · http://www.biodiversitylibrary.org/ · ISBN 0-486-20278-X ↩︎Two volumes, a comprehensive listing of N. American trees though a bit out of date now. Good details on habitats, some details on plant uses. Not really for the casual reader. It can be downloaded from the internet.
  15. [15]Trees of Central Texas. — Vines. R. A. · University of Texas Press · 1987 · ISBN 0-292-78958-3 ↩︎A good concise guide, it gives details of habitats and some of the uses of trees growing in Texas.
  16. [16]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.
  17. [17]Trees of North Texas — Vines. R.A. · University of Texas Press. · 1982 · ISBN 0292780206 ↩︎A readable guide to the area, it contains descriptions of the plants and their habitats with quite a bit of information on plant uses.
  18. [18]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.
  19. [PFAF]Plants for a Future — pfaf.org ↩︎