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Fagaceae FAMILY Least Concern

Quercus kelloggii

Quercus kelloggii

Edibility
4/5
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
Growth—

Quercus kelloggii grows in the mainly mediterranean climate of southwestern N. America, with wet, mild winters and hot, dry summers. Most of the annual precipitation (around 80 - 90%) falls from November to April. The mean annual precipitation ranges from 300 - 3,000mm, with up to 80% of total precipitation falling as snow. Summer temperatures can reach 39°c, with winter lows down to -20°c[2]. The plant usually grows well in areas with cooler summers, but then often does not fruit well[3]. Grows best in a sunny position[2], though young plants tolerate reasonable levels of side shade[4]. Requires a well-drained soil[2]. Prefers a good deep fertile loam, though it can also tolerate shallow, rocky soils[5, 3, 2]. Tolerates moderate exposure, surviving well but being somewhat stunted[4]. Established plants are highly drought tolerant[2]. California black oak was profoundly important to local Native American tribes. The acorns were a tribal food staple and many villages were located near the oak groves. The acorns were a primary source of tribal wealth and a much-desired trade item for desert tribes without ready access to acorns. Oak woodlands were managed as orchards on many sites - the trees were pruned, and stands thinned and burned to enhance acorn production[2]. California Black Oak acorns are still gathered by people of many different tribes in California and southern Oregon and known as the most edible of the oak acorns in the region. Although not currently so utilized, the acorns are a potential source for commercial food production[6]. A very ornamental plant, often grown as a shade tree[2]. The tree flowers on new growth produced in spring, the seed taking two summers to ripen[7]. Seedlings soon develop a taproot and become intolerant of root disturbance, they should be planted into their permanent positions whilst young[3]. The tree sprouts freely from the base if it is cut down or is top-killed by fire[2]. Fire is important habitat factor that promotes the growth of this species at the expense of others, especially conifers - it resprouts freely before the conifers can become re-established, allowing it to become the climax tree in the area[6]. Hybridizes freely with other members of the genus[4]. It hybridizes in the wild with Quercus agrifolia and Quercus wislizenii[8]. California Black Oak is particularly susceptible to fungi, especially heart rot of the bole and large limbs due to the pathogens Inonotus dryophila and Laetiporus sulphureus. Older trees, if infected, are often reduced to shells, and by the time a stand is 85 years old the proportion of infected trees begins to increase rapidly, growing to almost 40% infected at 110 years. However, there is not evidence that these pathogens are currently causing significant damage to the species[6]. This species is notably resistant to honey fungus[9, 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+kelloggii>

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]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
  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]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]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 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.
  8. [8]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.
  9. [9]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.
  10. [10]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.
  11. [11]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.
  12. [12]Common Edible and Useful Plants of the West. — Sweet. M. · Naturegraph Co. · 1962 · ISBN 0-911010-54-8 ↩︎Useful wild plants in Western N. America. A pocket guide.
  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]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.
  15. [15]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.
  16. [16]A Modern Herbal. — Grieve. · Penguin · 1984 · ISBN 0-14-046-440-9 ↩︎Not so modern (1930's?) but lots of information, mainly temperate plants.
  17. [17]Antibacterial and Antifungal Activities of Some Quercus Species Growing in Turkey — Didem Söhretoğlu; Melike Ekizoğlu; Ekrem Kiliç; M. Koray Sak · 2007 ↩︎
  18. [18]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
  19. [PFAF]Plants for a Future — pfaf.org ↩︎