Shade Trees

The trees listed below are recommended for boulevards without overhead power lines. These varieties should do well in what are often tough planting sites. The boulevard widths (the area from curb to sidewalk) can range from 6-15 feet wide, depending on the subdivision. With an up to an average of 8-foot width. Given this planting area, the goal is to have a selection of hardy tree species that are medium to large in height (35-65 feet) to produce shade, slow down storm water runoff, tolerate urban pollution, are relatively disease and insect free, and are aesthetically pleasing.

*Note, descriptions cited from certain nurseries are not an endorsement of that nursery. These are just citations to give credit for the information.*

Recommended Boulevard Trees

for boulevards with no overhead power lines

Amur Corktree

Seems to be winter hardy and slow growing.
No serious insect or disease problems.
Only male trees will be planted.
Prefers alkaline soils, moderately tolerant of road salt.

His Majesty Corktree
Phellodendron schalinense

University of MN introduction
Male Only
Height: 40'

Amur Corktree
Phellodendron amurense

Height: 30-45'
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Description Sources: Morton Arboretum and UMN Agricultural Experiment Station.

Birch

Fast Growing
Can be a multi-stemmed tree or trained to be a single-stemmed tree
If birches are stressed, they can be susceptible to bronze birch borer and killed. (Bronze birch borer is a native borer and does not cause problems to otherwise healthy birch trees.)

Prairie Dream Birch
Betula papyrifera 'Varen'

Excellent stress tolerance
Resistant to bronze birch borer
Height: 50'

Dakota Pinnacle Birch
Betula platyphulla 'Fargo'

Narrow column-like shape
Some resistance to bronze birch borer
Height: 35'

Description Sources: Missouri Botanical Garden and NDSU Woody Plant Improvement Program.

Black Walnut

A large oval to rounded, somewhat open-crowned tree.
Used extensively by over 20 species of wildlife for food and cover.
Produces walnuts.
Needs to be sited carefully because it produces a chemical that is toxic to some plants.
Grows to be 50-70' tall.
Tolerates alkaline soil, clay soil, and road salt.
One of the best woods for furniture among native trees.
Native Americans reportedly used the husks of the nut to throw into ponds to poison fish and make them easier to catch. (Missouri Botanical Garden)

Black Walnut
Juglins nigra

Intolerant of shade
Difficult to transplant due to deep tap root

Description Source: Missouri Botanical Society.

Buckeye

Hardy tree for the area
Ohio Buckeye is prone to leaf scorch
Produces a nut that attracts wildlife
Produces many flowers in spring and nuts in fall that attract wildlife
Moderately tolerant of alkaline soils, soil salt, and salt spray

Autumn Splendor Buckeye
Aesculus x arnoldiana 'Autumn Torch'

UMN introduction
Semi-glossy
Emerald green foliage
Red-purple fall color

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Description Source: NDSU Woody Plant Improvement Program, NDSU Ohio Buckeye Handbook, UMN Agriculture Experiment Station, and Morton Arboretum.

Elm

American Elm has been decimated by Dutch Elm Disease (DED) for decades.
All varieties are DED resistant.
Fast-growing and adaptable to tough sites.
Elms need frequent pruning in the first 15 years to help trees develop with good structure and strong branch attachments.

Discovery Elm
Ulmus davidiana var. japonica 'Discovery'

Highly resistant to Dutch elm disease
Height: 35-55'

Patriot Elm
Ulmus 'Patriot'

National Arboretum introduction
Vase shaped crown that can be more narrow than most elm cultivars
Excellent Dutch elm disease resistance
Height: 45'
Spread: 25'

Prairie Expedition Elm
Ulmus americana 'Lewis & Clark'

DED resistant NDSU introduction
Typical American elm form
Height: 55-60'

Triumph Elm
Ulmus 'Morton Glossy'

Morton Arbortum introduction with a sturdy, symmetrical growth habit
Good Dutch elm disease resistance
Height: 55'
Spread: 40'

Description Sources: UMN Extension, Morton Arboretum , and Missouri Botanical Society. Photo: Chicagoland Grows.

Gingko Biloba

This Species is being trialed for cold tolerance.
Reaches a height of 50-80 feet.
Tolerant of alkaline and acidic, compacted soils.
Tolerant of air pollution, heat, and salt.
Considered a living fossil, one of the longest-living tree species and has had fossils found from 270 million years ago.

Gingko Biloba
Gingko biloba

Fan-shaped leaves

Description Source: Arbor Day Foundation and Missouri Botanical Garden.

Hackberry

Has been used to replace elms lost to DED.
Has very unique bark and edible berries that can persist through the winter.
"The name hackberry originated from the Scottish "hagberry" which in England was the common name for bird cherry. (Iowa State University)
Tolerant to salt spray, pollution, and adaptable to many site locations.
More prone to decay after wounding or with large prune cuts. These should be structured pruned young to minimize wounding.

Common Hackberry
Celtis occidentalis

Height 50-75'
Spread 50'

Description Source: Iowa State University.

Honeylocust

Unique leaf structure gives dappled shade.
Very adaptable to drought and multiple soil conditions.
Medium sized tree that can be planted along boulevards or parking lots.
Tolerant of road salt.

Northern Acclaim Honeylocust
Gleditsia triacanthos var. inermis 'Harve'

Seedless and thorn-less NDSU introduction
Height: 40-50'

Skyline Honeylocust
Gledistsia triacanthos 'Skycole'

Mostly widely used honeylocust cultivar
Thornless and nearly seedless
Height: 45'
Spread: 35'

Street Keeper Honeylocust
Gledistsia triacanthos 'Draves' PP21698

Tight, narrow form creates a canopy half that of other cultivars
Thornless and largely seedless
Height: 45'
Spread: 20'

Description Sources: NDSU Woody Plant Improvement Program and Mortorn Arboretum.

Ironwood

Smaller, native species.
Has hop-like fruits, hence the alternative name, hop hornbeam.
Resistant to many disease and insect problems.
20-40' in height, slow growing.
Tolerates dry, alkaline, and clay soil.
Intolerant of salt.
Slow to establish.

Ironwood
Ostrya virginiana

Height 30'
Spread 25'

Description: Morton Arboretum.

Kentucky Coffeetree

Drought resistant, tolerant of pollution, and adaptable to a variety of soils.
Slow to moderate growth rate.
Forms a uniform, picturesque crown at maturity.
Reaches height of 60-75'.
Native to the Midwest.
Large mammals that lived millions of years ago probably ate the pods and dispersed the seeds.

"Native Americans made coffee from roasted, ground seeds (raw seeds are toxic), and European settlers apparently learned from them." (Missouri Department of Conservation)

Kentucky Coffeetree
Gymnocladus dioicus

If a female tree is planted, pods will grow in fall
These are only used in parks

Stately Manor Kentucky Coffeetree
Gymnocladus dioicus 'Stately Manor"

'Stately manor' University of MN introduction
Seedless selection

Espresso Kentucky Coffeetree
Gymnocladus dioicus 'Espresso'

Seedless selection
Arching branches provide a vase-like shape

Description Sources: Morten Arboretum and Missouri Department of Conservation.

Lindens

A native tree species.
Tend to perform well without major disease or insect problems.
Drop fruit bracts in summer, can be messy.
Flowers are loved by bees.
Has a tendency to form poor branch unions without early structural pruning.

Boulevard Linden
Tilia americana 'Boulevard'

Narrow pyramidal growth; height: 60'

Redmond Linden
Tilia americana 'Redmond'

Upright growth pattern, and will not droop as much as other linden species
Height: 60-70'

Frontyard Linden
Tilia americana 'Bailyard'

Symmetrical with dense foliage
Height: 60-75'

Greenspire Linden
Tilia cordata 'Greenspire'

Faster growth rate than other Lindens
Dense pyramidal to oval crown
Height: 40-60'

Harvest Gold Linden
Tilia mongolica 'Harvest Gold'

Upright tree, hybrid of a little leaf linden and a Mongolian linden
Height: 25-45'

Description Sources: Gilman and Watson (1994), NDSU Agriculture and University Extension, NDSU North Dakota Tree Selector, University of Florida IFAS Extension, and Greenwood Nursery.

Maple

A popular tree that can struggle in alkaline soils.
Clay County has alkaline soils, and this makes it more difficult for plants to take up iron and manganese, which can lead to iron chlorosis in maples. (yellowing leaves)
Tend to be over planted, which can lead to problems during insect or disease outbreaks

Green Mountain Sugar Maple
Acer saccharum 'Green Mountain'

Adaptable to alkaline soils
Rapid growth, resistant to leaf scorch
Height: 50-60'

Rugged Ridge Maple
Acer miyabei 'JFS-KW3AMI

Cultivar of Miyabe Maple
Corky bark provides protection from sunscald and winter damage
Height: 55'
Spread: 40'

State Street Miyabe Maple
Acer miyabei 'Morton'

Excellent heat and drought tolerance, as well as tolerance of alkaline soils
Has distinct corky bark
Height 30-40'

Description Sources: MN Department of Agriculture, Morton Arboretum, and Missouri Botanical Society.

Mountain Ash

Mountain ashes are members of the rose family, so they are not true ashes and are not hosts to the
emerald ash borer.
Tend to be small to medium-sized trees.
Susceptible to problems with iron chlorosis and fire blight.
Fruit attracts birds.
Sensitive to road salt