Practical
Plants

Ulmus thomasii

Rock Elm

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Taxonomy and growth

Family
Ulmaceae
Genus
Ulmus
Life cycle
perennial
Foliage
deciduous
Woodiness
woody
Growth rate
slow
Height
30 m
Fertility
Wind
Flower type
hermaphrodite
Pollinators
Wind

Uses

Edible uses

Leaves - raw or cooked.

Plant part
Leaves

Material uses

Wood - very strong, hard, heavy, tough, elastic, durable, close and beautifully grained, difficult to split. It weighs 45lb per cubic foot and is used for furniture, agricultural implements, wheel hubs and other purposes demanding toughness, solidity and flexibility[10][11][13][3][6][7][8].

Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy

Environment

Range
Central and Northeastern N. America - Quebec to Ontario, Minnesota, Kentucky, Missouri and Nebraska.
Habitat
Rich woods and calcareous uplands[9]. Dry gravelly uplands, low heavy clay soils, rocky slopes and river cliffs[13].
Light
full sun
Shade tolerance
light shade
Water
moderate
Hardiness
Zone 2+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - if sown in a cold frame as soon as it is ripe, it usually germinates within a few days[5]. Stored seed does not germinate so well and should be sown in early spring[5]. 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[12]. 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[5].

Cultivation

Prefers a deep fertile soil in full sun[4][7], but can be grown in any soil of at least moderate quality so long as it is well drained[1]. Plants are tolerant of poor soil conditions in the wild[7]. Although perfectly hardy, this species does not thrive in Britain[1][2]. It is very slow growing, even in its native range[2]. Susceptible to 'Dutch elm disease', a disease that has destroyed the greater part of all the elm trees growing in Britain. The disease is spread by means of beetles. 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[5]. 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[5].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2

  2. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2

  3. Hill. A. F. Economic Botany. The Maple Press 1952-00-00

    ↩

  4. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩

  5. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5

  6. Lauriault. J. Identification Guide to the Trees of Canada Fitzhenry and Whiteside, Ontario. 1989-00-00 ISBN 0889025649

    ↩

  7. Elias. T. The Complete Trees of N. America. Field Guide and Natural History. Van Nostrand Reinhold Co. 1980-00-00 ISBN 0442238622

    ↩1↩2↩3

  8. Britton. N. L. Brown. A. An Illustrated Flora of the Northern United States and Canada Dover Publications. New York. 1970-00-00 ISBN 0-486-22642-5

    ↩

  9. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

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  10. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩

  11. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

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  12. McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985-00-00 ISBN 0-901361-21-6

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  13. Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965-00-00 ISBN 0-486-20278-X

    ↩1↩2

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