Recommended Tree List | Tree Ordinance | Big Tree List

Recommended Tree List:

Co-Op Tree Planting Program-
Trees on our recommended list represent varieties that have show hardiness to Portland’s climate, display favorable characteristics and are generally available in the nursery trade.

Co-Op Nurseries offer excellent selections of shade and ornamental trees, including trees native to New England and interesting non-native ‘exotics’. Trees with * are readily available and especially recommended.

We group trees into the following categories: "Street trees", (St) are trees we recommend for planting between the sidewalk and street, or along street lines because they have desired characteristics such as branching heights, shape and hardiness to grow in urban conditions. Street-trees tend to include more ‘shade trees’ that are grown for shade vs. ornamental qualities. "Lawn trees", (L) are planted ‘setback’ away from the esplanade or street on the lawn area. Trees can be multi-stemmed or lower branched than the street-trees and may be less tolerant of urban conditions. "Lawn trees" include: ‘shade’, ‘ornamental’ and ‘conifer’ trees.

It is important to match the desired characteristics to the tree characteristics, (what do you want the tree to do?) Shade, screening, ornamental qualities such as flowers, fruit, or interesting bark, how big will it get and where does it do best? Wet or dry site, sun or shade? Fortunately, we have many more types of trees to choose from than ever before. Do not settle for one type without looking at the opportunities that are available at the nursery. "Plant the right tree, in the right location". Trees need room to grow... trees are not planted in small spaces between the sidewalk and the street that are under 3’ in width. In these areas we recommend 'set-back' planting behind the sidewalk and away from utilities. Ideally, trees should be setback 10’ from intersections, driveways, walks, utility poles and hydrants.

Please review the following web sites for more information:

The National Arboretum’s Award Winners
International Society of Arboriculture: Buying High-Quality Trees
International Society of Arboriculture: Tree Selection
UConn: Plant Database

We can offer further tree information along with the Co-Op Nurseries to assist with your tree selection. Note: Some street-tree locations may have desired tree types.

Tree Sizes
We recommend 1.75 - 2.5" caliper, or thickness of the trunk at the base, for street-tree planting and 1.5 - 2" for lawns.

Co-Op Program limits trees to:
3" caliper for shade and ornamental trees and 6-7’ Height for conifers.

Small Trees
Grow to an average of 20' to 30' feet in height. Small trees are often planted along streets under overhead utility lines, or spaces where a small tree is desired, this group offers the most ornamental characteristics such as flowers and fruit.

Maples, Acer
There are several interesting and useful small Maples that deserve attention, including:.

Hedge Maple, Acer campestre (*,ST,L)
Grows slowly to a height of 25’ to 30’ according to reference materials, however, we have several trees that after 20 years are just approaching 15’ in height.

Amur Maple, Acer ginnala (L)
A small speciman tree, hardy, good fall color, available with single or multi-stem trunks, grows to a height of 15-20’.

Paperbark Maple, Acer griseum (*,L)
A small specimen tree with interesting exfoliating bark and good fall color, planted in lawn areas only, hard to find, may want to use a smaller size. Beautiful small specimen tree.

‘Rocky Mtn. Glow’, Acer gradidentatumn (ST,L)
Western Sugar Maple, - Recently available, smaller then the native Sugar Maple grows up to 30’ with round shape.

Three-flowered Maple, Acer triflorum (ST,L)
A unique small specimen tree, exfoliating bark, tri-foliate leaves that turn yellowish / red fall color.

Purpleblow or Shantung Maple, Acer truncatum, (ST,L)
Reddish purple leaves when emerging turning to dark glossy green. 20’ H by 10’ W.

Shadbush, Amelanchier
Native tree with white or pink flowers in the spring. Available with single (ST) or multi-stemmed (L) trunks and is best used in moist areas with light shade. Not for dry compacted spaces, better for lawn areas than small tree-lawn spaces between the sidewalk and street. ‘Cumulus’ is a single stem tree form with white flowers, ‘Robin Hill’ is single stem with pink flowers.

Hawthorns, Crataegus
Flowers in June and is noted for its red berries in the winter. There are many interesting varieties including: ‘Winter King’ (L), ‘Washington’ (ST) and ‘Crusgalli’ * (thorn-less) (L,ST for land areas and esplanades).

Flowering Crabapple, Malus
There are many types with different shapes, flowers, leaf, and fruit colors. Our favorite varieties include: ‘Spring Snow’ (ST,L), ‘Snowdrift’ (ST,L), and ‘Harvest Gold’ (L), ‘Donald Wyman’, and ‘Sargent’ for lawn areas and (L) ‘Pinkspire’ and ‘Sentinel’ for narrow sites.

Magnolias (L)
Used as specimens and planted in lawn areas only. Many varieties and cultivars available, check with your Co-Op Nursery for availability.

Cherry, Prunus
One of the first flowering trees in the spring. ‘Accolade’ (ST,L); 'Amur chokecherry’ (L) has pink/white flowers and interesting bark, for lawn areas only.

Tree Lilac *, Syringa*
Tree form lilac with white flowers. Available with single (ST) and multi- stem trunks (L), Tree lilacs have performed well as street-trees under utility lines in areas. Requires ample, non-compacted, growing space. s.

‘Leprechaun’ Ash, Fraxinus pennsyvanica (ST,L)
A small, slow growing 15’ x 15’ cultivar. Good tree for smaller areas.

The following small trees are great for the lawn area behind the sidewalk, but not as street trees.

Dogwood, Cornus kousa (*)
Kousa and the new Rutgers Hybrids, C. kousa x C. florida, are recommended specimen trees for lawn areas, white or pink flowers, single and multi-stemmed forms. Many cultivars exist.

White Fringe Tree, Chionanthus (*)
Beautiful small tree with white flowers in June.

Sourwood, Oxydendrum arboreum
Excellent specimen tree with late summer bloom. Truly, a great small tree for late summer and early Fall. Scarce, available in small sizes.

Stewartia, Stewartia pseudocamellia and koreana (L)
Flowers in July and has beautiful exfoliating bark. Longfellow Arboretum in Payson Park has a beautiful specimen planted in 1976.

‘Arnolds’ Promise’ Whitchhazel, Hamamelis x intermedia
Yellow flowers in early March, the first plant to flower in Maine. Whitchhazel is a shrub that can grow 10’ in height, its early flowers are an inspiration that Spring is coming. This is the only shrub on our list and deserves to be planted more. Specimens planted at Post Office Park, Hadlock Field and gardens on the ‘West End’, all have faired well with regular flowering in March, for lawn areas only.

Medium to Large Sized Trees
Shade and Ornamental trees grow 30' to 50' in height.

River Birch, Betula nigra (*,L)
An often overlooked birch with creamy white to brownish bark. River Birch have fewer insect problems than the Paper Birch. See the grove of River Birch at the Longfellow Arboretum along the Payson Park roadway.

American or European Hornbeam
Carpinus caroliniana & Carpinus betulus
A nice small to medium sized, compact tree in single-stemmed (ST) and multi-stemmed (L) forms. The bark and leaves are similar to beech trees. Upright forms are useful for screening or hedges. Hornbeam makes an excellent screen, does best in non-compacted lawn areas vs. tree well situations

Katsuratree, Cercidiphyllum (*,L)
This is a unique tree with heart shaped leaves that open as reddish purple, turn bluish-green, and then turn to yellow-orange in the fall. This interesting tree can be seen at the Longfellow Arboretum in Payson Park.

American Yellowood, Cladrastis (*,L)
This tree has compound leaves and white flowers blossoming in June. Deering Oaks Park, State Street at Park Avenue on the left

Turkish Filbert, Corylus colurna (*,ST,L)
We have been planting Filbert’s for seven years with very good results. It’s hardy, has interesting light colored, rough bark and should grow to 30’.

Honeylocust, Gleditsia (*,ST,L)
Thornless honeylocusts have small compound leaves that cast a light filtered shade. Honeylocusts are medium sized trees in Maine and are able to grow in difficult sites as a lawn or street tree. Some recommended varieties include ‘Skyline’ and ‘Halka.’ Honeylocusts due to there branching habit can often be planted under or closer to utility lines than most medium or large trees with necessary pruning.

Callery Pear, Pyrus calleryana (ST,L)
Although many new varieties have replaced the original ‘Bradford’ type, this name is often used to describe the newer ones. ‘Cleveland Select’ is one of the improved varieties along with ‘Redspire’ and ‘Aristocrat.’ Pears are beginning to be over planted and are prone to storm damage.

Korean Mountain Ash, Sorbus alnifolia (*,ST,L)
This is a beautiful tree which has a different appearance than the common European Mountain Ash. The Korean Mountain Ash has beech-like foliage and bark, white flowers in June, and pinkish-red berries in fall and winter that attract birds. Although it may be hard to find, it is becoming a very popular tree. Flowers after crabapples and pears.

American Hophornbeam, Ostrya virginiana (L)
Native tree with interesting bark, lawn areas, does not grow too large, can tolerate shade.

Large Trees
50' and up. Shade Trees.
Large trees should not be planted under or close to utility lines.

Red Maple, Acer rubrum (*,ST,L)
Native maple with red leaves in the fall. It tolerates wet sites and is more salt-tolerant than Sugar Maples. There are many new cultivars and Red Maple / Silver Maple hybrids.

'Armstrong’ Red Maple - upright cultivar seen in the Old Port area.
‘Karpick’ Red Maple* - more open with a upright / oval form.
‘Autumn Blaze’ Red Maple* – larger, fast growing hybrid with great Fall color.

Sugar Maple, Acer saccharum* (ST,L)
Native maple with yellow-orange fall foliage. Upright cultivars are available for narrow spaces. Not salt tolerant.

Catalpa, Catalpa (L)
White flowers bloom in June and seedpods develop in the fall. This tree has an interesting winter form and should be planted in lawn areas because it needs room to grow.

Beech, Fagus (L)
American and European varieties exist. There are many leaf shapes with color ranging from green to purple. Standard beeches are best planted in lawn areas or behind sidewalks because it needs some room to grow. We have seen upright varieties as successful street trees in the Western Prom area. Many interesting cultivars exist, including ‘Riversi’ that has purple leaves, and ‘Aspenifolia’ that has fern-like leaves.

Ash, Fraxinus (ST,L)
Green and White Ash are large, fast growing shade trees. The Green Ash is more common and has bright yellow fall foliage. Some varieties include ‘Summit’ and ‘Patmore.’ The White Ash has varieties such as ‘Autumn Purple’ and ‘Empire’, is a new upright selection. ‘Leprechaun’ Ash* is a small 15’ round shaped tree for smaller areas.

Ginkgo, Ginkgo biloba (*,ST,L)
A truly unique tree with fan-shaped leaves and an interesting history. Ginkgos are slow growing after transplanting, but grow well in difficult sites.

Tuliptree, Liriodendron (ST,L)
Tulip shaped leaves with an interesting flower blooming at the top of the tree. Large, fast growing tree that needs room, interesting tree. Maine’s largest Tuliptree is on Munjoy Hill.

Cucumber Magnolia, Magnolia acuminata (L)
A large shade-tree magnolia that does not have the showy spring flowers of other Magnolias. It is an interesting tree, although it is scarce. A beautiful specimen is on Brackett Street at Walker Street.

Tupelo, Nyssa sylvatica (*,L)
Native, rare tree that can tolerate damp sites and is slow growing after transplanting. It has a bright red fall color. Maine’s largest is near O’Donal’s Nurseries. Ferry Beach State Park in Saco has a beautiful stand of Tupelo.

Oak, Quercus (L)
(Street trees only where ample planting space exists) There are many varieties of native oak including the common Red Oak, Pin Oak, Chestnut Oak*, White Oak, and Swamp White Oak*. These long-lived, big trees need room to grow but are one of the best native trees. The Swamp White Oak has beautiful glossy foliage and exfoliating bark. Pin Oaks are easily established. Two forms of English Oak, Quercus robur, ‘Skymaster*’ (pyramidal) and ‘Skyrocket*’ (columnar) can be planted in more restrictive areas including as ‘street-trees’.

Linden, Tilia (ST,L)
A good medium to large shade tree flowering in June. Lindens often suffer some insect damage from Japanese beetles and aphids. Numerous cultivars of European, Little-leaf and native Basswood are available. Varieties include: ‘Legend*’, ‘Redmond*’ (Basswoods), ‘Greenspire*,’ and ‘Sterling’ or Silver Linden. Baxter Boulevard’s lindens are dedicated to Portland’s World War l veterans.

Elm, Ulmus (ST,L)
Once the most popular of all trees, Dutch elm disease has caused and continues to be a severe problem. New resistant varieties have shown promise in resistance to Dutch elm disease, ‘Patriot’, ‘Princeton’, ‘Pioneer’, and ‘Lacebark’ Ulmus parvifolia. Limited availability.

Zelkova (ST,L)
A vase shaped tree that was hoped to replace the American Elm…Zelkovas are vase-shaped but smaller than elms. Difficult branching angles can cause some problems later on if not pruned correctly. Many beautiful specimens exist in the West End near Danforth Street.

Conifers & Evergreens -

For lawn planting only!
Conifers & evergreens are a great addition to the landscape. In the past conifer planting was often limited to planting a small Blue Spruce or rows of White Pine. Note – many evergreens can quickly outgrow a small space, take time to review growth rate and size. Nurseries now offer many new sellections with many sizes and shapes. We recommend the following:

Pine, Pinus
Swiss Stone(*) Pinus cembra, small, (30’) slow growing with soft blue green needles. See nice specimen at the Spring Point Shoreway Arboretum in South Portland. Others: ‘Vanderwolf’(*) Pine, p. flexlis, very narrow, upright with soft blue-green needles. ‘Lacebark Pine’, p. bungeana, 30’H x 20’W, spreading and open shape with pealing bark. ‘Regular’ pines such as White, Red, Scotch and Austrian all have their unique characteristics.

Spruce, Picea
Serbian(*) (good upright form), Norway Spruce offers pendulous branching, White Spruce is a good ‘native’ spruce. Serbian Spruce is not as wide, and is better for lawn areas. Blue Spruce often suffer from insect problems and out-grow their site. Oriental Spruce is a variety that has become more available showing good characteristics.

Fir, Abie
Concolor Fir*, Balsam and Frasier Firs are used as Christmas trees. Moderate growth rate and large mature size.
Concolor Fir has great soft blue-green foliage, see nice speciman in Deering Oaks Park near the Rose Circle.

Deciduous Conifers
Offer the shape and screening of an evergreen, but during the winter months allow sunlight. TYPES: (Lawn use only) Dawn Redwood or Metasequoia*, Baldcypress, Taxodium distichum, and Japanese Larch, Larix kaempferi*, are three underused and beautiful deciduous conifers, consider them as ‘evergreens’ that loose their needles. Great for lawn areas, naturalized or as specimens, they have the advantage of allowing winter sun as they drop their needles in the Fall with great fall color and texture.

NOTE:
Portland, Maine is USDA Plant Hardiness Zone 5B. Select trees hardy to Zone 5 and lower.