Fall is an excellent time to plant new trees. Why not consider an elm?

An elm?!? What??

Elms have certainly gotten a bad reputation, and people rarely think of them when needing to plant a new shade tree. Dutch elm disease has wiped out nearly 100 million American elms in America since 1930. In addition to its American elms, Colorado Springs also has many Siberian elms growing in the area. This tree’s reputation as a “trash tree” is well deserved. It is highly vulnerable to damage by elm leaf beetles, succumbs to bacterial wetwood, plants thousands of volunteer seedlings annually, and drops twigs whenever it is stressed (and it is always stressed).

However, work has been ongoing to develop hybrid elms with resistance to Dutch elm disease, and here are a few that the Colorado Nursery Association thinks are worth planting:
‘Homestead,’ ‘Pioneer,’ and ‘Sapporo Autumn Gold.” These hybrids grow 30’ to 40’ tall with about a 30’ spread. Leaves turn yellow-to-gold in the fall. (Note that the Forestry division of Colorado Springs Parks and Recreation still doesn’t recommend these as street trees because of the possible damage they may cause to sidewalks, but they are still worth planting in other areas of your landscape if you have the space for them.) The association also recommends a new rounded, weeping form of Scotch Elm, Ulmus glabra ‘Camperdownii.’ This elm is smaller, growing 10-to-15’ tall with a much wider spread, 25-30’.

ulmus_parvifola_bark.jpg

Ulmus parviflora bark

Colorado Springs Parks and Recreation does recommend trying the Chinese elm (Ulmus parviflora) as a street tree. People in our area often refer to their weedy Siberian elms (Ulmus pumila) as Chinese elms. Siberian elms and Chinese elms are not the same tree. The Chinese (or Lacebark) elm is a much more attractive and desirable tree! Highly adaptable to different soils and climates, it is also strongly resistant to Dutch elm disease and to elm leaf beetle damage. One of its most attractive features is its colorful exfoliating bark, in colors from gray, green, and brown, to orange.

Each year, the city has had to cut down many American elms growing in the medians downtown. To replace some of these trees, it is trying a new disease-resistant hybrid called ‘Accolade’ – a cross between Chinese and Japanese species.

Michael Dirr, author of Dirr’s Hardy Trees and Shrubs also recommends the following new varieties of the Chinese elm (Ulmus parviflora):
Allee® – similar looking to American wlm with gray to orange-brown exfoliating bark
Athena® – a broader shape that is slightly shorter, 30-35’ tall
King’s Choice® – a rapid growing variety (one specimen grew to 22’ tall, 16’ wide in seven years)

Another possibility worth consideration is the Japanese zelkova tree (Zelkova serrata), a close relative to our more familiar elms. This tree is similar in shape to the American elm, but not quite as majestic. It grows 40-to-60’ tall, but it takes a bit of pruning to get a good tree shape. It has shown tolerance to high heat conditions and drought. This is another tree recommended for street tree planting by the Colorado Springs Parks and Recreation department.

Contributed by Carey Harrington, Certified Colorado Gardener

Sources: Dirr’s Hardy Trees and Shrubs, Michael Dirr.
“Trees for Colorado Springs,” Colorado Springs Parks and Recreation (Urban Forestry)

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