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Rock Elm, Cork Elm
Ulmus thomasii

Family: Ulmaceae (ulm-AY-see-ee) (Info)
Genus: Ulmus (ULM-us) (Info)
Species: thomasii (to-MAS-ee-eye) (Info)

Category:

Trees

Height:

over 40 ft. (12 m)

Spacing:

30-40 ft. (9-12 m)

over 40 ft. (12 m)

Hardiness:

USDA Zone 3b: to -37.2 C (-35 F)

USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

Sun Exposure:

Full Sun

Sun to Partial Shade

Danger:

Unknown - Tell us

Bloom Color:

Pale Green

Green

Bloom Time:

Late Winter/Early Spring

Mid Spring

Foliage:

Deciduous

Shiny/Glossy-Textured

Good Fall Color

Other details:

This plant is attractive to bees, butterflies and/or birds

Average Water Needs; Water regularly; do not overwater

Soil pH requirements:

5.6 to 6.0 (acidic)

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

Patent Information:

Unknown - Tell us

Propagation Methods:

From softwood cuttings

From semi-hardwood cuttings

From seed; direct sow outdoors in fall

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

Regional

This plant has been said to grow in the following regions:

Champaign, Illinois

Gardeners' Notes:

1
positive
1
neutral
0
negatives
RatingContent
Positive

On May 20, 2011, srhill from Champaign, IL wrote:

My experience is that the seeds must be planted immediately while still green and fresh, in the Spring. They seem to be killed by drying. Extremely slow growing elm. Becoming rare - needs more propagation !

Neutral

On Apr 8, 2005, melody from Benton, KY (Zone 7a) wrote:

Information only, I do not grow this plant.

This tree has a wonderful straight trunk and is a valuable hardwood. It is found in moist to dry uplands, rocky ridges and limestone bluffs.

It's range is from S. Ontario and S. Quebec, through New England south to TN and West to KS.

The very hard wood is difficult to split, making it valuable for tool handles. In the 19th century, the wood was exported to England for the construction of wooden battleships and sailing vessels.