The chestnut cultivar Colossal originates from the USA - California Central Valley. It is a ''

Castanea sativa ''Castanea sativa'', the sweet chestnut, Spanish chestnut or just chestnut, is a species of tree in the family Fagaceae, native to Southern Europe and Asia Minor, and widely cultivated throughout the temperate world. A substantial, long-lived ...

'' × ''

Castanea crenata ''Castanea crenata'', the Japanese chestnut, also known as the Korean chestnut is a species of chestnut native to Japan and Korea. ''Castanea crenata'' exhibits resistance to ''Phytophthora cinnamomi'', the fungal pathogen that causes ink diseas ...

'' hybrid that is cold hardy to . The tree can be grown in Zones 4-8, blooms early, and is pollen sterile. Colossal is

chestnut blight The pathogenic fungus ''Cryphonectria parasitica'' (formerly ''Endothia parasitica'') is a member of the Ascomycota (sac fungi). This necrotrophic fungus is native to East Asia and South East Asia and was introduced into Europe and North America ...

root rot Root rot is a condition in which anoxic conditions in the soil or potting media around the roots of a plant cause them to rot. This occurs due to excessive standing water around the roots. It is found in both indoor and outdoor plants, althoug ...

and kernel rot susceptible.

History

It is probable that ‘Colossal’ was a seedling of one of Felix Gillet’s high quality French (Castanea sativa) cultivars, pollinized by a Japanese (Castanea crenata) tree. The original Colossal tree and its pollinizer were planted in approximately 1888-1890 by Benjamin Tonella in

Nevada City, California Nevada City (originally, ''Ustumah'', a Nisenan village; later, Nevada, Deer Creek Dry Diggins, and Caldwell's Upper Store) is the county seat of Nevada County, California, United States, northeast of Sacramento, southwest of Reno and northea ...

The most likely source for the trees was The Barren Hill Nursery of Felix Gillet. Gillet imported some of the best French chestnut cultivars and also imported an assortment of Japanese chestnuts. Gillet died in 1908 and the nursery was bought by C. E. Parsons. Parsons introduced the Colossal chestnut commercially in 1925. In 2000, the original ‘Colossal’ tree was over tall, with a spread of over and a trunk circumference approaching .

Culture

Colossal tree growth is vigorous but the wood is somewhat weak. Reportedly, heavily loaded spreading branches can break under high burr load or in strong wind For almost all American commercial chestnut growers the Colossal chestnut tree is the producer of the largest nuts and the most nuts. Colossal orchards require interspersed planting of

pollenizer {{Unreferenced, date=May 2009 A pollenizer (or polleniser), sometimes pollinizer (or polliniser, see spelling differences) is a plant that provides pollen. The word '' pollinator'' is often used when ''pollenizer'' is more precise. A pollinato ...

s. Results from wind-pollination and hand-pollination experiments in Michigan strongly suggest that the highest Colossal nut production is achieved when pollen is available at

anthesis Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period. The onset of anthesis is spectacular in some species. In ''Banksia'' species, for example, anthesis involves the extension ...

. Anthesis in mid-Michigan is generally between late-June and early-July. Grafted trees may start producing at a young age within the first few years of transplanting. Nuts usually fall early and free of the burrs. Nuts can be large 11-15 per pound (~25g/nut). Usually there are 3 nuts per burr. Colossal nuts have occurrence of double or triple embryos per nut. The pellicle (skin) of the nuts is thick. Fresh refrigerated nuts should be consumed within 90 days because Colossal nuts do not store well. The taste of Colossal nuts is average with high sucrose content.Warmund MR, et al
Descriptive sensory analysis and free sugar contents of chestnut cultivars grown in North America
J Sci Food Agric. 2011. accessed 2018 There are other cultivars, where chestnuts rank higher in taste tests. In the California central valley, under ideal conditions, Colossal orchards can produce of nuts per acre. Due to early bud break, late spring frosts can cause damage on early leaves and buds.

References

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Sources

* Anagnostakis, Sandra L. The Connecticut Agricultural Experiment Statio
CULTIVARS OF CHESTNUT
2013, accessed 2017 * Vossen, Paul
Chestnut culture in California
Publication 810, 2000, accessed 2018 Chestnut cultivars Edible nuts and seeds