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Sapindaceae FAMILY

Aesculus californica

Aesculus californica

Edibility
3/5
Medicinal
2/5

Safety & Hazards

All parts of the plant are poisonous, containing the glycoside esculin, the saponin aescin, and possibly alkaloids. Ingestion can cause muscular weakness and paralysis, dilated pupils, vomiting, diarrhea, depression, paralysis, and stupor[1]. Honeybees are the chief pollinators of this tree, but the pollen and nectar are toxic to them. Losses of adult honeybees and their larvae due to poisoning can be severe[2]. The seed is rich in saponins. Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans. Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins. Saponins are much more toxic to many cold-blooded creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish and make them easy to catch[PFAF].

Cultivation Details

HabitDeciduous Tree
GrowthMedium

Aesculus californica is moderately cold tolerant, though it grows best in areas where winter temperatures do not fall below -10°c. It does not do well in areas with higher rainfalls - in Britain for example it grows well in the east and south-east, but less well in the moister west[3, 4]. Requires a position in full sun[4]. Prefers dry sunny locations[5]. Prefers a deep loamy well-drained soil but is not too fussy[3]. A moderately fast-growing and long-lived tree in the wild[6]. Seedlings quickly develop a taproot and larger plants can be difficult to transplant[7].

Propagation

Seed - best sown outdoors or in a cold frame as soon as it is ripe[3, 8]. The seed germinates almost immediately and must be given protection from severe weather[9]. Seedlings develop a large taproot following germination and so, if grown in containers, should be given sufficient root room[10]. The seed has a very limited viability and must not be allowed to dry out. Stored seed should be soaked for 24 hours prior to sowing and even after this may still not be viable[8, 11]. It is best to sow the seed with its 'scar' downwards[9]. If sowing the seed in a cold frame, pot up the seedlings in early spring and plant them out into their permanent positions in the summer. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Aesculus+californica>

Pollinators

Bees

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]The Plantsman. Vol. 6. 1984 - 1985. — ? · Royal Horticultural Society · 1984 · ISBN - ↩︎Excerpts from the periodical giving cultivation details and other notes on some of the useful plants including Actinidia and Wisteria species.
  6. [6]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.
  7. [7]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.
  8. [8]Hardy Woody Plants from Seed. — McMillan-Browse. P. · Grower Books · 1985 · ISBN 0-901361-21-6 ↩︎Does not deal with many species but it is very comprehensive on those that it does cover. Not for casual reading.
  9. [9]The Plantsman. Vol. 4. 1982 - 1983. — ? · Royal Horticultural Society · 1982 · ISBN - ↩︎Excerpts from the periodical giving cultivation details and other notes on some of the useful plants, including Distylium racemosum and some perennial members of the family Berberidaceae.
  10. [10]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.
  11. [11]The Reference Manual of Woody Plant Propagation. — Dirr. M. A. and Heuser. M. W. · Athens Ga. Varsity Press · 1987 · ISBN 0942375009 ↩︎A very detailed book on propagating trees. Not for the casual reader.
  12. [12]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.
  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]Shrubs. — Phillips. R. & Rix. M. · Pan Books · 1989 · ISBN 0-330-30258-2 ↩︎Excellent photographs and a terse description of 1,900 species and cultivars.
  15. [15]Alternative Foods. — Sholto-Douglas. J. ↩︎Not very comprehensive, it seems more or less like a copy of earlier writings with little added.
  16. [16]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.
  17. [17]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.
  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]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.
  20. [20]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.
  21. [21]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.
  22. [22]Earth Medicine, Earth Food. — Weiner. M. A. · Ballantine Books · 1980 · ISBN 0-449-90589-6 ↩︎A nice book to read though it is difficult to look up individual plants since the book is divided into separate sections dealing with the different medicinal uses plus a section on edible plants. Common names are used instead of botanical.
  23. [23]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.
  24. [24]A Weavers Garden — Buchanan. R. · McGraw-Hill Contemporary · 1987 · ISBN 0934026289 ↩︎Covers all aspects of growing your own clothes, from fibre plants to dyes.
  25. [PFAF]Plants for a Future — pfaf.org ↩︎