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Fagaceae FAMILY Least Concern

Quercus agrifolia

Quercus agrifolia

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

HabitEvergreen Tree
GrowthSlow

Quercus agrifolia is not very cold-hardy, tolerating temperatures falling to around -8°c when dormant. It grows in a mediterranean climate, characterized by mild, wet winters and hot, dry summers. It generally adapts well to maritime climates, though will often not fruit well unless the summers are hot[2, 3, 4]. Trees fruited very heavily at Kew Gardens, London (hardiness zone 7 - 8) in the hot summer of 1989[PFAF]. Prefers a good deep fertile loam which can be on the stiff side[5, 2]. Plants are lime tolerant[6]. Young plants tolerate reasonable levels of side shade[7]. Tolerates moderate exposure, surviving well but being somewhat stunted[7]. Established plants are moderately drought resistant[8]. Seedlings soon develop a taproot and become intolerant of root disturbance, they should be planted into their permanent positions whilst young[2]. As trees grow older, the taproot usually becomes non-functional, the tree developing an extensive system of surface roots[8]. Native Americans used to plant the seeds of this tree in favoured positions so that they could harvested the acorns for food. The tree is planted as an ornamental, often being used as a street tree or in parks etc[8]. A slow-growing but long-lived tree in the wild, with trees more than 250 years old[9, 8]. The tree flowers on new growth produced in spring, the seed ripening in its first year[7, 9]. The bark of mature trees is thick and can protect the tree from moderate fires, though severe fires will usually kill top growth[8]. Trees can resprout from the trunk and/or root crown if they are felled or top-killed by fire[8]. This is the dominant tree in California's southern and central coastal oak woodlands, and populates the chaparral phase of the southern oak woodland as a shrub[10]. The bark of immature trees is smooth and develops deep ridges with age, with branches often reaching the ground in areas lacking grazing. Providing some of the most important habitats for many insects, birds and mammals in California, Quercus agrifolia also feeds many birds and rodents with its acorns, and provides a critical source of food for Black-tailed Deer with its foliage[10] Hybridizes freely with other members of the genus[7]. This species reportedly hybridizes with Quercus kelloggii and Quercus wislizenii[11]. Mature Quercus agrifolia are very susceptible to sudden oak death, which can wipe out an initially healthy tree within a few weeks to several years. In California the disease has reached "epidemic proportions" and there is particular risk on California's central coast[10]. This species is notably resistant to honey fungus[12, 7].

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[2]. 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+agrifolia>

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]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.
  3. [3]Shrubs for the Milder Counties. — Arnold-Forster. ↩︎Trees and shrubs that grow well in Cornwall and other mild areas of Britain. Fairly good, a standard reference book.
  4. [4]Trees and Shrubs in Cornwall. — Thurston. ↩︎Trees and shrubs that succeed in Cornwall based on the authors own observations. Good but rather dated.
  5. [5]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 ]).
  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]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.
  8. [8]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
  9. [9]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.
  10. [10]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.
  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]The Garden. Volume 112. — RHS. · Royal Horticultural Society · 1987 · ISBN - ↩︎Snippets of information from the magazine of the RHS. In particular, there are articles on plants that are resistant to honey fungus, oriental vegetables, Cimicifuga spp, Passiflora species and Cucurbits.
  13. [13]A California Flora. — Munz P.A. & Keck D.D. · University of California Press; Los Angeles · 1959 · ISBN - ↩︎An excellent flora but no pictures. 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]Sturtevant's Edible Plants of the World. — Hedrick. U. P. · Dover Publications · 1972 · ISBN 0-486-20459-6 ↩︎Lots of entries, quite a lot of information in most entries and references.
  16. [16]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.
  17. [17]A Field Guide to the Common and Interesting Plants of Baja California. — Coyle. J. and Roberts. N. C. · Natural History Publishing Co. · 1975 · ISBN - ↩︎A very readable pocket flora with good illustrations, it gives quite a few plant uses.
  18. [18]Early Uses of Californian Plants. — Balls. E. K. · University of California Press · 1975 · ISBN 0-520-00072-2 ↩︎A nice readable book.
  19. [19]Edible and Useful Wild Plants of the United States and Canada. — Saunders. C. F. · Dover Publications · 1976 · ISBN 0-486-23310-3 ↩︎Useful wild plants of America. A pocket guide.
  20. [20]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.
  21. [21]A Modern Herbal. — Grieve. · Penguin · 1984 · ISBN 0-14-046-440-9 ↩︎Not so modern (1930's?) but lots of information, mainly temperate plants.
  22. [22]Antibacterial and Antifungal Activities of Some Quercus Species Growing in Turkey — Didem Söhretoğlu; Melike Ekizoğlu; Ekrem Kiliç; M. Koray Sak · 2007 ↩︎
  23. [23]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
  24. [24]Flora of Guatemala — Standley P.C. & J. A. Steyermark · 1946 - 1976 · http://www.archive.org/ ↩︎A superb reference, though somewhat dated. Gives lots of plant uses as well as information on plant habit and habitat. The entire flora (13 volumes) can now be downloaded from http://www.archive.org/
  25. [PFAF]Plants for a Future — pfaf.org ↩︎