Tree of the Month May/June 2018
by: Lesley Bruce Smith, ISA Certified Arborist
When I was a little girl, like many who grew up in communities east of the Mississippi River, I lived on a street lined with American Elms. Although it is against every piece of advise we now share, to line streets with the exact same species, I can’t help but think back in wonder at those amazing cathedral like arches that lined so many American City streets in the last century. It is a memory held by so many of us over the age of 50 that it is little wonder that so much hybridizing has been done with the American Elm. It comes from a desire to achieve another city champion tree like it. Our fondness for American Elms is well founded, and although planting monocultures of the same species is NEVER a healthy or sustainable plan, it was an amazing tree before Dutch Elm Disease hit. (reference Tree of the Month, January 2014) It was able to handle all the abuse we threw at it in urban environments. It would grow in constricted and compacted soils, like those found in parkways and along city streets. It was graceful and elegant and that is why we planted so many of them, and it is also why horticulturists have worked to hybridize the American Elm, by crossing it with other species of European and Asian Elms that are resistant to Dutch Elm Disease.
It is time to take a look at some of these hybrids which all share some of the characteristics of the American Elm favorite. One of our mentors, Dr. George Ware who worked at The Morton Arboretum was a champion of the American Elm hybridization program. He worked quite tirelessly in the last part of his career hybridizing Elm species to achieve a comparable Elm tree. The Accolade Elm is one of the better hybrids. The Morton Arboretum, because of Dr. Ware’s influence, has a great list of Elm cultivars available on their website at mortonarb.org. The list gives species names and characteristics of the hybrids that have been brought to market. The Morton Arboretum is also a great place to go see these Elms in real life. There is also an alley of Hybrid Elms at the Chicago Botanic Garden in the garden green that is north of the Education Center. Next time you are contemplating a new tree for planting be sure to check out the many lovely and hardy Hybrid Elms.