Family Ulmaceae - Zelkovas, Hackberries and Elms

There are about 200 species of trees and shrubs in Ulmaceae: 14 trees and 2 shrubs are native to North America. The Elms fell victim to Dutch Elm disease during the 1950's; until that time, they were the premiere shade tree along the streets of our towns and cities.

Nikko Elm
Ulmus laciniata

Siberian Elm
Ulmus pumila

Japanese Zelkova
Zelkova serrata

Japanese Zelkova
Z. serrata v. 'Green Vase'

Zelkova serrata
Var. 'Village Green'

American Elms show prototypical vase shape of the Ulmus genus.

The Morton Arboretum, at Lisle, Illinois, where these pictures were taken, is home to the largest Elm collection in North America. Under study, the collection includes almost all of the 22 Elm species native to China, a dozen of which show resistance to Dutch elm disease and elm yellows. The Arboretum in past years has bred and marketed five new elm varieties resistant to Dutch elm disease.

The 12 species being studied are: the Bergmann (Ulmus bergmanniana), Taihang Mountain (U. taihangshanensis), Tibetan (U. microcarpa), Anhui (U. gaussenii), Hebei (U. lamellosa), Harbin (U. harbinensis), corkbark (U. propinqua var. suberosa), plum-leaved (U. prunifolia), Chenmou (Ulmus chenmoui), Gansu (Ulmus glaucescens var. lasiocarpa), chestnut-leaved (U. castaneifolia) and Father David (U. davidiana var. mandshurica) elms.

These 12 Chinese trees are virtually unknown in the U.S., but are under close study at the arboretum. Dendrologist Emeritus and former research director Dr. George Ware, and Arboretum Assistant Director of Collections Kunso Kim are responsible for their observation and data collection. Their efforts may help ameliorate the effects of numerous maladies affecting trees around the world, such as Emerald Ash Borer, Oak wilt, Asian Longhorned Beetle, Pine Sawyer Beetle, et al.

"These and other problems underscore the urgent need for the Arboretum and others to continue seeking new species for urban use," Kim says. The average lifespan of an urban tree is fewer than 10 years, according to Ware. But planting hardier trees increases the likelihood of a longer life and a greener world - a goal that has never been more important than now, with climate change upon us. [2]

Cedar Elm	Jersey Elm	Large-fruited Elm	Dropmore Siberian Elm
Chinese Elm Ulmus parvifolia	Hybrid Elm Ulmus (carpinifolia x pumila)	Corkbark Elm Ulmus propinqua var. suberosa	Rock Elm Ulmus thomasii
Accolade Elm Ulmus 'Morton'	Klemmer Holland Elm Ulmus x hollandica 'Klemmer'	Bergmann's Elm Ulmus bergmanniana	Russian Elm Ulmus laevis

When I was a child in the late 1950's, Thacker Street in Des Plaines, Illinois, was lined with huge American Elms. We walked to school shaded by those magnificent trees; they were so tall, their branches overarched the street completely. It was a wonderful walk then, and especially in fall when our mornings were bathed in yellow light filtering through the glorious butter-yellow foliage. Of course, we gathered leaves to take into school with us, to trace and do rubbings with fat Crayons from our (newly introduced) 64 packs.

But when the school year started in 1960, those trees had all been cut down, victims of Dutch Elm Disease. It was so sad, and now we walked under blazing sun and boy, did we miss those trees. Similar scenarios are now playing themselves out amongst the lodgepole pine and ash trees of North America.