Ulmus carpinifolia x parvifolia ‘Frontier’
Given the vigor and tolerance of most elm trees, several new cultivars should be back on our preferred street tree lists. But how do we compare them? New disease and insect resistant varieties seem to be popping up all over. There are so many with different forms, textures, and other qualities, where does one start?
One of the most unique varieties I have seen recently is the Frontier Elm tree. The Frontier Elm appears to be a small to intermediate size tree, maybe reaching 40′ and possibly as wide, although early growth appears to be narrower. It has small leaves, with a moderately strong central leader and upright, pyramidal growth. Of most interest is its reddish purple fall color, a striking change from the more typical fall yellow color of most elms. In the nursery, this is a fast growing tree with great visual appeal. It is easy to transplant, but unlike most elms, does not appear to be as drought tolerant.
The literature claims this hybrid elm exhibits a high level of disease tolerance to the fungus that causes Dutch Elm Disease, and moderate resistance to the Elm Leaf Beetle in laboratory and field tests. In addition, the Frontier Elm appears highly tolerant to natural infections of elm yellows. This is an elm cultivar, released in 1990, with spring flowering (Ulmus carpinifolia) and fall flowering (Ulmus parvifolia) parents. So far no seed production has occurred.
This tree is a sleeper. It has good vigor, tolerates poor soils, grows fast, but does not get big. It also has small leaves and no seed, resistant of insect and disease problems, with outstanding fall color. The Frontier Elm tree should be on everyone’s street tree list.
What has your experience been with this tree or others? Let me know!
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Jim Barborinas
Owner of Urban Forest Nursery, Inc.
ISA Certified Arborist #0135
ASCA Registered Consulting Arborist #356
15119 McLean Rd.
Mount Vernon, WA 98273
jim@urbanforestnursery.com
Curious how Frontier Elm performs in landscapes and streetscapes?
Here are some common questions people ask about this tree:
Frontier Elm is a small to intermediate-sized elm with striking reddish-purple fall color. It has small leaves, a moderately strong central leader, and upright, pyramidal growth. It’s fast-growing and highly appealing visually.
It reaches about 40 feet tall and roughly the same in spread, with an upright, pyramidal canopy and moderately strong central leader.
Its standout feature is the reddish-purple fall foliage, which provides a dramatic contrast to the typical yellow of other elms. Leaves remain small and well-formed, contributing to clean structure.
It transplants easily and grows well in poor soils, but unlike most elms, it’s not especially drought tolerant. Its small size and disease resistance make it a good choice for street planting where space is limited.
This elm is resistant to Dutch Elm Disease, Elm Leaf Beetle, and elm yellows, with no seed production. Its vigorous growth and tidy habit make maintenance minimal, and it’s well suited to street and urban landscapes.