New Harmony American Elm

You might be too young to remember, but perhaps you are not. Once upon a time the American elm was an iconic tree in our cities, lining every street in avenues that took advantage of its characteristic vase-shaped form. Tens of millions of these trees brought beauty and shade to large and small communities. Then disaster struck. Between 1930 and 1990 – mostly in the 50s, 60s, and 70s – almost 60 million trees died all across the country from Dutch Elm Disease, a fungal disease spread by bark beetles and accidentally introduced from Europe, where it had only recently broken out. Today many gardeners, tree lovers and lovers of beautiful cities still miss the American elm, for its beauty and for its toughness. Just as we saw with the Covid pandemic, not everyone is affected, and some have natural immunity. This is rare among elm trees, but now, thanks to 20 years of tireless work by the Maryland Agricultural Research Service, we can now offer you the New Harmony American Elm tree. Not 100% immune, but almost, it won the National Elm Trials, beating better-known names like ‘Valley Forge’. If you miss our wonderful American elm, then this is your chance. This newer tree is also superior in growth and in form, recapturing the classic vase-shape of arching branches that makes this tree so instantly-recognizable. Wow, finally.

Growing the New Harmony American Elm

Size and Appearance

The New Harmony American Elm is a fast-growing deciduous tree, adding 3 feet a year once established and while young, maturing into a large shade tree up to 65 feet tall. The branches arch out from the top of the trunk, forming a vase-shaped crown that will be up to 70 feet across. Remember those dimensions when choosing a planting place, and don’t plant anywhere near overhead wires. Plant at least 30 feet from buildings and not close to your property line without the agreement of neighbors. This is a long-lived tree and deserves a chance to live that long life. This tree develops a tall trunk, which becomes broad, up to 3 feet across. The branches rise vertically at first and then arch over, forming a broad crown high in the air, throwing lots of shade. The bark is rough and irregular, mottled in shades of dark and lighter brown, and gray, with long vertical ridges running down the trunk. The leaves are 3 to 6 inches long, and oval, with a smooth, glossy surface and a characteristic irregular base – one side is longer than the other. The edges are neatly serrated into pointed teeth, with further small serrations along those – called double-serration. A warm, deep green, the leaves turn a beautiful clear, glowing gold in fall. Older trees will flower, carrying hanging clusters of small white flowers from the branches before the leaves emerge. These can develop into clusters of flat, papery seeds ¾ inch across, which flutter to the ground in May, without making any significant litter.

Using the New Harmony American Elm in Your Garden

This magnificent tree is a natural for a shade tree on a large lawn. Fast-growing, it will soon be big enough to throw a useful shadow. Grow it as an avenue along a driveway or private road, spacing the trees at least 30 feet apart. Use it at the edge of natural woodland, and even make it into a bonsai, but it is as a single specimen or an avenue that it is most beautiful.

Hardiness

The New Harmony American Elm is incredibly hardy, growing well in zone 4 and even in warmer parts of zone 3. It is also reliable across a wide climate range, taking hot and humid summers and growing well in zone 10. Once established it is drought tolerant, although there is a connection between stress from drought and disease, so an occasional deep soaking of young trees would be a good idea.

Sun Exposure and Soil Conditions

A mature elm needs to be in full sun, but young trees will grow in partial shade, and this may even be helpful in encouraging the tree to grow tall and upright, giving a better vase-shape when mature. It grows very well in just about any soil, another reason for its popularity. Although it prefers best to be in deep, rich and well-drained soils, it will grow happily in both acidic and alkaline ones, sands or clays, and tolerates wetter soils too. It is also resistant to the effects of de-icing salt. This is an amazingly adaptable tree that will grow almost anywhere, even with air pollution and poor soil.

Maintenance and Pruning

The New Harmony American Elm is normally free of any significant pests. As for Dutch Elm Disease, it won the National Elm Trials, held between 2005 and 2015, with an 85.5% survival rate. Not 100%, but in the natural world nothing is perfect. It also came second in trials where trees were deliberately infected, an even stronger test. We can’t guarantee that at some point in the future your tree won’t become infected, but there is a very good chance it won’t. If yours is the only elm tree in your neighborhood you have an even better chance.

To have the best mature tree possible, keep the main trunk free of small branches, taking off a few every year or two, to avoid the scars from removing bigger branches. Remove any crowded branches from the crown at the same time. Keep a single central trunk (leader) for as long as possible.

History and Origin of the New Harmony American Elm

The New Harmony American Elm was found as a natural tree growing along Interstate 70 near Springfield, Ohio. Plants were made from pieces of that tree in 1980. It was assessed at the Maryland Agricultural Research Service of the US Department of Agriculture by A. M. Townsend and L. R. Schreiber, top authorities on the American Elm and Dutch Elm Disease. It proved very successful, combining excellent disease resistance with vigorous growth and the development of the classic vase-shaped crown that is so desirable in this tree. It was released by the National Arboretum to growers in 1994, but not made available to the public until 2004, after over 20 years of assessment.

Buying the New Harmony American Elm at the Tree Center

We are excited to have found some stock of this great tree, genetically identical to that first Ohio tree. The New Harmony American Elm is certainly the best looking of all the possible modern varieties, and almost certainly the most disease-resistant. Now is your chance to bring back this iconic tree, but order now – everyone misses it, and everyone wants to grow one.