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Ulmaceae FAMILY

Ulmus thomasii

Ulmus thomasii

Edibility
2/5
Medicinal
2/5

Safety & Hazards

None known

Cultivation Details

HabitDeciduous Tree
GrowthSlow

Ulmus thomasii is native to the continental climate of central and eastern N. America, with its cold winters and warm summers. It dislikes maritime climates. It can experience summer temperatures as high as 38°c and winter temperatures as low as -34°c, with a frost-free period ranging from 100 - 200 days[1]. Mean annual rainfall can range from 640 - 1,270mm, usually spread through the year. Prefers a deep fertile soil in full sun[2, 3], but can be grown in any soil of at least moderate quality so long as it is well drained[4]. Plants are tolerant of poor soil conditions in the wild[3]. Found in the wild on slightly alkaline to strongly acid soils[1]. A very slow growing tree, even in its native range[5]. This species is susceptible to 'Dutch elm disease'[6], a disease that has destroyed the greater part of all the native elm trees growing in countries such as Britain and USA. The disease is spread by means of beetles. Mature trees killed back by the disease will often regrow from suckers, but these too will succumb when they get larger. There is no effective cure (1992) for the problem, but most E. Asian, though not Himalayan, species are resistant (though not immune) to the disease so the potential exists to use these resistant species to develop new resistant hybrids with the native species[7]. This species hybridizes with Ulmus pumila and Ulmus laevis[1]. The various species of this genus hybridize freely with each other and pollen is easily saved, so even those species with different flowering times can be hybridized[7].

Propagation

Seed - if sown in a cold frame as soon as it is ripe, it usually germinates within a few days[7]. Stored seed does not germinate so well and should be sown in early spring[7]. The seed can also be harvested 'green' (when it has fully developed but before it dries on the tree) and sown immediately in a cold frame. It should germinate very quickly and will produce a larger plant by the end of the growing season[8]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Plants should not be allowed to grow for more than two years in a nursery bed since they form a tap root and will then move badly. Layering of suckers or coppiced shoots[7]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Ulmus+thomasii>

Pollinators

Wind

References

  1. [1]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.
  2. [2]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.
  3. [3]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.
  4. [4]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 ]).
  5. [5]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.
  6. [6]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.
  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]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]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.
  10. [10]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.
  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]Ulmus davidiana var. japonica Nakai Upregulates Eosinophils and Suppresses Th1 and Th17 Cells in the Small Intestine — Lee H-S, Jang MS, Kim J-H, Hong C-P, Lee E-J, et al · 2013 ↩︎
  13. [13]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.
  14. [14]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.
  15. [15]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.
  16. [16]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.
  17. [17]An Illustrated Flora of the Northern United States and Canada — Britton. N. L. Brown. A. · Dover Publications. New York. · 1970 · ISBN 0-486-22642-5 ↩︎Reprint of a 1913 Flora, but still a very useful book.
  18. [PFAF]Plants for a Future — pfaf.org ↩︎