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Fagaceae FAMILY Least Concern

Quercus macrocarpa

Quercus macrocarpa

Edibility
3/5
Medicinal
2/5

Safety & Hazards

All parts of the plant contain tannins. Whilst tannins are found in many foods, and have a range of medicinal uses. They are usually only present in low concentrations. In some foods made from oaks (particularly the seeds), the tannin content can be quite high unless the food is treated to reduce tannin content. Tannins are only of low toxicity and, because of their bitter taste and astringency, are unlikely to be eaten in large quantities. However, if they are taken in excess, they can cause stomach pains; constipation followed by bloody diarrhoea: excessive thirst; and excessive urination[1].

Cultivation Details

HabitDeciduous Tree
GrowthSlow

Quercus macrocarpa is a very cold-hardy plant, tolerating temperatures down to about -35°c when dormant[2]. It grows best in areas with hot summers. In areas with cooler summers, such as the maritime regions of the temperate zone, it often grows poorly, failing to properly ripen its wood and suffering frost damage over the winter[3, 4]. A tree at the Hillier Arboretum in Hampshire, southern England was growing well in September 1993. It was 9 metres tall but had a lot of mildew, there was no sign of seeds[PFAF]. Grows best in a sunny position[5], though young plants tolerate reasonable levels of side shade[4]. Prefers a good deep fertile loam which can be on the stiff side[3]. The tree is usually found in the wild on limestone or calcareous clay soils[6]. Succeeds in a hot dry position. The plant endures a wide variety of harsh conditions including poor dry soils and wet, poorly drained, and inundated locations[6]. Tolerates moderate exposure, surviving well but being somewhat stunted[4]. A slow-growing tree[7]. Established plants are drought resistant[8] and tolerant of atmospheric pollution[9]. Occasionally cultivated for its edible seed, there are some named varieties[10]. The main sources of Quercus macrocarpa trees for timber are Iowa and Illinois bottomlands[6]. The tree flowers on new growth produced in spring, the seed ripening in its first year[4, 8]. The large acorns are best developed in the southern part of the range, and a clinal decrease in acorn size and extent of the mossy fringe on the acorn cup seems to occur as one travels from south to north[11]. It is a slow-growing but fairly long-lived species, reaching ages of 300 - 400 years old; some plants have been documented to reach up to 450 years of age[6]. It takes about 30 years to start producing seed, though it then continues to crop for the next 200 - 300 years with large crops being produced every 2 - 3 years[8]. This species is the state tree of Illinois[5]. Hybridizes freely with other members of the genus[4]. Putative hybrids with Quercus bicolor are common in the northeastern part of its range, where the two species often occur together in wet, poorly drained habitats. The effect of this contact may be partially responsible for morphologic differences across the range of Quercus macrocarpa[11]. Trees have a thick, fire-resistant bark[12]. There is a dwarf form of this species:- Quercus macrocarpa depressa (Nutt.)Engelm., grows about 2 metres tall with corky branches and smaller seeds than the species, usually about 10mm long[13]. Plants in this genus are notably resistant to honey fungus[4].

Propagation

Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool overwinter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees[3]. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Quercus+macrocarpa>

Pollinators

Wind

References

  1. [1]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.
  2. [2]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
  3. [3]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  4. [4]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.
  5. [5]KemperCentreForHomeGardeningPlantFinder — Missouri Botanical Garden · http://www.mobot.org/gardeninghelp/plantfinder/ ↩︎Basic cultivation details, plant uses, habitat etc for several thousand species of plants, mainly from the temperate zone.
  6. [6]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.
  7. [7]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.
  8. [8]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.
  9. [9]Identification Guide to the Trees of Canada — Lauriault. J. · Fitzhenry and Whiteside, Ontario. · 1989 · ISBN 0889025649 ↩︎Very good on identification for non-experts, the book also has a lot of information on plant uses.
  10. [10]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.
  11. [11]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
  12. [12]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.
  13. [13]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.
  14. [14]Fire Effects Information System — http://www.feis-crs.org/feis/ ↩︎An on-line information site with comprehensive information on over 1,100 species of plant. Mainly developed to supply information on the effects of fire on plants and animals, it also contains a wealth of other information on the plants
  15. [15]Gray's Manual of Botany.Eighth Edition — Fernald. M. L. · American Book Co.; New York · 1950 · ISBN 0442222505 ↩︎A bit dated but a good and concise flora of the eastern part of N. America.
  16. [16]Edible Wild Fruits and Nuts of Canada. — Turner. N. J. and Szczawinski. A. · National Museum of Natural Sciences · 1978 · ISBN - ↩︎A very readable guide to some wild foods of Canada.
  17. [17]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.
  18. [18]Food Plants of the N. American Indians. — Yanovsky. E. · U.S. Depf of Agriculture. · ISBN - ↩︎A comprehensive but very terse guide. Not for the casual reader.
  19. [19]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.
  20. [20]Wild Food Plants of Indiana. — McPherson. A. and S. · Indiana University Press · 1977 · ISBN 0-253-28925-4 ↩︎A nice pocket guide to this region of America.
  21. [21]A Dictionary of Plants Used by Man. — Usher. G. · Constable · 1974 · ISBN 0094579202 ↩︎Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.
  22. [22]A Modern Herbal. — Grieve. · Penguin · 1984 · ISBN 0-14-046-440-9 ↩︎Not so modern (1930's?) but lots of information, mainly temperate plants.
  23. [23]Antibacterial and Antifungal Activities of Some Quercus Species Growing in Turkey — Didem Söhretoğlu; Melike Ekizoğlu; Ekrem Kiliç; M. Koray Sak · 2007 ↩︎
  24. [24]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
  25. [25]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.
  26. [26]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.
  27. [27]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.
  28. [28]Economic Botany. — Hill. A. F. · The Maple Press · 1952 · ISBN - ↩︎Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
  29. [PFAF]Plants for a Future — pfaf.org ↩︎