The Elms & Hackberries

Siberian Elm Common Hackberry Slippery Elm Dwarf Hackberry

What are they?

Elms are found throughout the Northern temperate zone of the world, with the greatest number of species in Central Asia and China. Elms were once much-cherished as shade trees and for their wood, but a fungal disease, transmitted by a small bark-burrowing beetle, has spread rapidly throughout Europe and North America (due in no small part to the trade in plants between countries) and the sight of stately, native elms in many parts of the world is now a thing of the past. Some species remain resistent however, and new, resistent strains of other species are gradually being developed and planted. There appear to be no native elms in the Cape May region, all plants seemingly originating from plantings. Hackberries are found in many countries and are known as nettle trees in Europe. In North America there are a number of very similar species, making species identification often problematic.

Where are they found?

Large elms are mostly found around habitation where they have been planted, but younger, self-sown plants occur from time to time on field edges and abandoned land. Hackberries are trees of open, scrubby woodland and field edges.

Identification

Some elm species can be difficult to identify but those around Cape May should be relatively easy with careful attention to the leaves. Some of the first trees to flower in the region, opening at the same time as Red and Silver Maples. Hackberries are very difficult to identify as many of the reference books give contradictory identification criteria. Attention should be paid to the leaves and fruits and identification is thus easiest in late summer and fall.



American Elm      Ulmus americana

Not native in Cape May County and only found as a relic of cultivation. Far less common than Siberian Elm, but there are a few sizeable specimens along route 9 north of Cape May Court House. Flowers March to April. Differs from Siberian Elm in having flowers on longer stalks and leaf edges that are doubly serrate.
American Elm American Elm American Elm American Elm
Tree in winter
Leaf margin
double-toothed
Flowers with
stamens opening
Flowers with
stigmas expanding

American Elm American Elm American Elm
Winged seed capsule
Winter buds
Bark

Siberian Elm      Ulmus pumila

A variable tree, according to climate. In the mid-west this tree was once widely planted for its drought tolerance; the result (somewhat inevitably!) is that it is now a serious invasive alien in many areas, though growing conditions keep it as a rather small, bushy tree. Around Cape May, the species is more stately and can grow to a great height. Doesn't seem to regenerate rapidly in Cape May County, though it is rather common in old fields and hedgelines in some areas. Flowers March to April. Differs from American Elm in having flowers (and seed capsules) on longer stalks and margins of leaves single- not double-toothed.
Siberian Elm Siberian Elm Siberian Elm Siberian Elm
Leaves
Leaf margin
single-toothed
Flowers with
stamens ripe
Flowers with
stigmas ripe

Siberian Elm Siberian Elm Siberian Elm Siberian Elm
Seed capsules
Winter flower buds
Winter leaf bud
Bark

Chinese Elm      Ulmus parvifolia

A small to medium-sized tree, grown as an ornamental and introduced from Asia. Not established in the wild in Cape May, but not uncommon as an ornamental in park or street plantings and included here as some publications have wrongly used this name for specimens of Siberian Elm in the area. Flowers October to November. Very unlike most other elm species in its ornamental, flaking bark, thick, almost evergreen, small leaves and its autumn-flowering habit.
Chinese Elm Chinese Elm Chinese Elm
Habit
Leaves
Leaves

Chinese Elm Chinese Elm Chinese Elm Chinese Elm
Young Seed capsules
Mature Seed capsules
Winter bud
Bark

Common Hackberry      Celtis occidentalis

Distribution unclear in Cape May County and probably not native here, but plants fitting descriptions of this species in literature are not uncommon in the County and may originate as the result of plantings of introduced stock. Flowers May. A confused group of trees as there is much disagreement as to identification characters between the available reference sources. Supposed features of this species include leaves which are serrated to well below the midpoint and fruits which have pedicels (stems) that are longer than the leaf petioles. Fruit color variable.
Common Hackberry Common Hackberry Common Hackberry Common Hackberry
Habit of young trees
Leaf
Winter bud
Bark on young tree

Dwarf Hackberry      Celtis tenuifolia

Distribution unclear in Cape May County, but said by some authorities to be the typical hackberry species in Cape May County. Trees found in coastal dune areas are presumed to be this species, but many appear to show intermediate characters between this and Common Hackberry. Flowers May. A confused group of trees as there is much disagreement as to identification characters between the available reference sources. Supposed features of this species include leaves which are only serrated towards the tip and fruits which have pedicels (stems) that are not longer than the leaf petioles. Fruit color variable.
Dwarf Hackberry Dwarf Hackberry Dwarf Hackberry Dwarf Hackberry
Habit
Leaf
Leaves and fruit
Fruit

Dwarf Hackberry Dwarf Hackberry
Winter bud
Bark

Common Hop      Humulus lupulus

A native, twining perennial, but perhaps also introduced from Europe. A plant of rich, loamy soils which appears to be rare in our area. Flowers July-August.
Common Hop Common Hop Common Hop
Trailing branch
Leaf
Twining stems

Japanese Hop      Humulus japonicus

Introduced from Asia. Recorded in the past as an escape from cultivation but rarely grown these days. Flowers July-August. Differs from Common Hop by its five- to seven-lobed, not three-lobed, leaves.
Japanese Hop
Leaf