Rock Elm, Cork Elm
Ulmusthomasii

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

Category
Trees

Water Requirements
Average Water Needs; Water regularly; do not overwater

Sun Exposure
Full Sun
Sun to Partial Shade

Foliage
Deciduous
Textured

Foliage Color

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)

Where to Grow

Danger
N/A

Bloom Color
Pale Green
Chartreuse (yellow-green)

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

Bloom Size

Bloom Time
Late Winter/Early Spring
Mid Spring

Other details

Soil pH requirements
5.6 to 6.0 (acidic)
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)

Patent Information
Non-patented

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