White elm
- Latin name: Ulmus americana L.
- French name: Orme d'Amérique
- Synonym(s): American elm
- Taxonomic Serial Number: 19049
Description
Leaves
Form
- Moderately rough, occasionally smooth
- Lower surface slightly hairy
- 15–20 veins per side, not more than 2 or 3 forked
Length
- 10–15 cm
Colour
- Upper surface dark green
- Lower surface paler
Autumn colour
- Yellow
Buds
Form
- Somewhat flattened, blunt
- End bud bent, others pressed against the twig
- 6–9 scales, sometimes slightly hairy
Length
- 5 mm
Colour
- Reddish-brown, margins darker
Margin
- Hairy
Twigs
Form
- Often zigzag, hairless or slightly hairy
- Lenticels inconspicuous
Colour
- Greyish-brown
Flowers
Form
- Each on a separate stalk, in loose, few-flowered, tassel-like clusters (fascicles)
Structure
- Synoecious
Fruits
Form
- Oval, veined, fringed with hairs, otherwise hairless
- Wing deeply notched at the tip
- Seedcase distinct
Length
- 8–10 mm
Bark
Form
- Deeply furrowed with broad, oblique, intersecting ridges, becoming scaly with age
Colour
- Dark greyish-brown, becoming mottled ash-grey with age
- Outer bark shows alternating layers of light orange-brown and dark brown
Size
Height
- To 35 m
Diameter
- To 175 cm
Maximum age
- 200 years
Tree form
Forest-grown
Trunk
- Buttressed at the base with prominent root flares
- Divides into a few large, upright limbs and many outwardly fanning branches
Crown
- Graceful, spreading, vase- or umbrella-shaped
- Branch tips often droop
Root system
Shallow, wide-spreading
Habitat
Site
- Wet sites and alluvial flats where water often remains in the spring
- Rich, moist, sandy or gravelly loams with good drainage
Light tolerance
- Moderately shade-tolerant, but grows better in full sunlight
Photos
Photos
Anthony Scullion
Insects and mites
Insects that cause damage to this tree.
-
Elm leafminer
Scientific name: Kaliofenusa ulmi Sundevall
-
Fall cankerworm
Scientific name: Alsophila pometaria [Harris]
-
Pale winged grey
Scientific name: Iridopsis ephyraria (Wlk.)
Foliage or buds
-
Elm leaf beetle
Scientific name: Xanthogaleruca luteola (Müller)
-
Elm leafminer
Scientific name: Kaliofenusa ulmi Sundevall
-
Fall cankerworm
Scientific name: Alsophila pometaria [Harris]
-
Fall webworm
Scientific name: Hyphantria cunea (Drury)
-
Mourningcloak butterfly or spiny elm caterpillar
Scientific name: Nymphalis antiopa (Linnaeus)
-
Saddled prominent
Scientific name: Heterocampa guttivitta Walker
Roots, bark, stem or trunk, or branches
Diseases caused by pathogens
Diseases caused by pathogens that cause damage to this tree.
-
Nectria dieback
Pathogen name: Nectria cinnabarina (Tode:Fr.) Fr.
-
Xylaria root rot
Pathogen name: Xylaria polymorpha (Pers.) Grev.
Foliage or buds
Dutch elm disease
Pathogen names:
-
Ophiostoma ulmi
(Buisman) Nannf.
- Ophiostoma novo-ulmi Brasier
- Ophiostoma ulmi (Buisman) Nannf.
-
Dutch elm disease
Pathogen names:
-
Ophiostoma ulmi
(Buisman) Nannf.
- Ophiostoma novo-ulmi Brasier
- Ophiostoma ulmi (Buisman) Nannf.
-
Ophiostoma ulmi
(Buisman) Nannf.
Roots, bark, stem or trunk, or branches
Dutch elm disease
Pathogen names:
-
Ophiostoma ulmi
(Buisman) Nannf.
- Ophiostoma novo-ulmi Brasier
- Ophiostoma ulmi (Buisman) Nannf.
White spongy trunk rot
Pathogen name: Fomes fomentarius (L.) Fr. (Common name for this fungus: tinder conk)
Distribution map
