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Portland's Recommended Tree List:
Trees on our recommended list represent varieties that have shown hardiness to our Portland, Maine climate, display favorable characteristics and are generally available in the nursery trade. Co-Op Nurseries offer a wide selection of shade and ornamental trees, including trees native to New England along with interesting non-native ‘exotics’. Trees with * are readily available and especially recommended.
Trees are grouped into the following categories: "Street trees" (ST) which are trees recommend for planting between the sidewalk and street, or along street lines due to desired characteristics such as branching height, 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 ‘setback’, planted away from the esplanade or street on the lawn area. They 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 ‘conifers’.
It is important to match the desired characteristics of the tree to the site where the tree is intended to grow. ‘Plant the right tree - in the right place’. Shade, screening, ornamental qualities such as flowers, fruit, or interesting bark, how big will the tree grow and where will it grow best? What are the site conditions - wet or dry, sun or shade? Trees need room to grow, picture the mature tree size growing in the location you plant to plant the new tree.
Planting Site Guidelines -
Trees planted in sidewalk ‘treewells’ have a minimum width of 3.5’ / leaving 3’ for wheelchair and pedestrian travelway. In restricted areas we recommend ‘setback’ tree planting behind the sidewalk. Trees must be set planted 10’ from intersections, driveways, walks, utility poles and fire hydrants.
Tree Planting Web site links -
Please review the following web sites for more information:
US Forest Service – Good checklist to plan for a new tree. www.na.fs.fed.us/spfo/pubs/uf/plant_trees/planting_trees.htm
ISA – International Society of Arboriculture ‘Trees Are Good’ web
site.
For info on how to select a tree -
www.treesaregood.org/treecare/buying_highquality.aspx
For info on how to plant a tree - www.treesaregood.org/treecare/tree_planting.aspx
National Arborday Foundation: ‘Right tree for the right place’ www.arborday.org/trees/rightTreeAndPlace/index.cfm
Cornell University ‘Urban Horticulture Institute’ tree selections www.hort.cornell.edu/uhi/outreach/recurbtree/index.html
UConn: Plant Database www.hort.uconn.edu/Plants
US National Arboretum www.usna.usda.gov
Cary Award Trees / Shrubs http://www.caryaward.org
Tree Size Recommendations 1.75” - 2.5" caliper, or thickness of the trunk at the base, for street-tree planting and 1.5” - 2" for lawn planting. Maximum sizes -3" caliper for shade and ornamental trees and 6-7’ Height for conifers. Co-Op Program limits trees to: 3" caliper for shade and ornamental trees and 6-7’ Height for conifers.
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THE TREES ON THIS LIST HAVE BEEN EVALUATED
FOR THE FOLLOWING CRITERIA:
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*
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Trees that are readily available and are especially recommended. |
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ST
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STREET TREE Recommended for ‘Street-tree’ planting in esplanades, between the sidewalk and the street, or along street lines for their ability to grow in urban conditions. Shade trees and ornamental trees are in this group. |
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L
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LAWN TREE Shade, ornamental, or conifer with single or multiple stem or trunks, low-branched or small tree forms recommended for ‘Lawn planting’, set back away from the roadway. |
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Trees are listed by both Common Name and
Scientific or Botanical name. |
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Small Trees 15’ – 25’
Small trees are often planted along streets under overhead utility
lines and for restricted space where a smaller tree is desired,
this group offer many ornamental characteristics such as flowers
and fruit.
Hedge Maple*, Acer campestre*
Uses: 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.
Paperbark Maple,
Acer griseum Uses: LAWN AREAS only.
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. Grows best in sheltered areas. See at Longfellow
Arboretum in Payson Park.
‘Rocky Mtn. Glow’,
Acer gradidentatumn Uses: ST / L
Western Sugar or Canyon Maple – Slow growing & smaller in size
then native Sugar Maple grows up to 25’ with round to oval
shape. As with Sugar Maples we advise not to plant near areas
that use high amounts of de-icing salts in winter. See:
www.jfschmidt.com/pdfs/rockymtnglowmaple.pdf
Three-flowered Maple, Acer triflorum
Uses: ST / L
A unique small specimen tree, nice exfoliating bark, tri-foliate
leaves that turn yellowish red fall color. See at Longfellow
Arboretum in Payson Park.
Korean Maple, Acer sieboldianum
Uses: LAWN AREAS only.
Small maple with good fall color, trees are often multi-stem & low branched.
Shadbush,
Amelanchier tree form, Uses: LAWN AREAS only.
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.
Good alternative to ‘Callery’ or Bradford Pear.
Hawthorns, Crataegus
Uses: L / ST
Flowers in June and is noted for its red berries in the winter.
There are many interesting varieties including: ‘Winter King’
(Lawns), ‘‘Crusgalli’ (Thorn-less) (Lawns & wide esplanades).
Crusgali has glossy foliage and is hardy in dry locations.
Flowering Crabapple, Malus
Uses: L / ST
There are many varieties with different attributes of shape,
flower, foliage, and fruit. Our favorite varieties include:
‘Adirondack’, ‘Spring Snow’ (fruitless), ‘Snowdrift’ (ST,L), and
‘Harvest Gold’ (L), ‘Donald Wyman’, and ‘Sargent’ for lawn areas
and (L) ‘Pinkspire’ and ‘Sentinel’ for narrow sites. Crabapple
varieties with larger fruit are not recommended.
Magnolias
Uses: Lawn areas only.
Used as specimens and planted in lawn areas only. ‘Centennial’ and
‘Dr. Merrill’ are recommended cultivars. ‘Leonard Messel’ offers a
pink flower. Many more cultivars are now available, check with
your Co-op Nursery for availability.
Cherry,
Prunus Uses: L / ST
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
reticulate Uses: L / ST
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.
‘Leprechaun’ Ash,
Fraxinus
pennsyvanica Uses: ST under utility wires.
A small, slow growing 15’ x 15’ cultivar. Good tree for smaller areas. Not
widely available.
The following small trees are great for the lawn area behind the sidewalk, but not as street trees.
Dogwood,
Cornus kousa Lawn areas only.
Kousa and the new Rutgers Hybrids, C. kousa x C. florida, are
recommended specimen trees for lawn areas, white or pink flowers.
White
Fringe Tree,
Chionanthus Lawn areas only.
Beautiful small tree with white flowers in June. Available as a multi-stem shrub
form.
American Hophornbeam, Ostrya
virginiana Uses: Lawn areas, Native to Maine.
Native tree with interesting bark, lawn areas, does not grow too large,
tolerates shade, ‘understory’ tree.
Sourwood,
Oxydendrum arboreum Lawn areas only.
Excellent small specimen tree with late summer bloom. Truly, a great small tree
for late summer and early Fall bloom & great Fall color. Scarce, available in
small sizes.
Stewartia,
Stewartia pseudocamellia and koreana Lawn
areas only.
Flowers in July and has beautiful exfoliating bark. Longfellow Arboretum in
Payson Park has a beautiful specimen planted in 1976.
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Medium Sized Trees 25’ - 45’
Shade and Ornamental trees grow 30' to 50' in height.
River Birch,
Betula nigra Uses: Lawn or
landscape areas only.
Fast growing birch with creamy white to brownish bark. River Birch
have fewer insect & disease problems than the Paper Birch. See
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 Uses: Lawn areas.
This is a unique tree with heart shaped leaves that open as reddish purple, turn
green, with yellow-orange Fall color. This interesting tree can be seen at the
Longfellow Arboretum in Payson Park.
American
Yellowood,
Cladrastis Uses: Lawn / Street-tree with ample room.
Compound leaves and white flowers blossoming bi-yearly in June. Locations
-Deering Oaks Park, State Street at Park Avenue on the left
Turkish
Filbert,
Corylus colurna Uses: Street-tree.
We have been planting Filbert’s for over 10 years with good results. It’s hardy,
has interesting light colored, rough bark and should grow to 35’.
Honeylocust,
Gleditsia
Uses: Street-tree.
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. 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.
Tupelo*, Nyssa sylvatica
Uses: Lawn,
Native, rare shade tree that can tolerate damp sites and is slow growing after
transplanting. Fall foliage is right red. Maine’s largest is near O’Donal’s
Nurseries. Ferry Beach State Park in Saco has a beautiful stand of Tupelo.
Korean Mountainash,
Sorbus alnifolia Uses: Lawn areas,
Street-tree
This is a beautiful tree which has a different appearance than the common
European Mountainash. The Korean Mountainash has beech-like foliage and bark,
white flowers in June, and pinkish-red berries in fall and winter.
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Large Trees 50’ +
Large trees should not be planted under or close to utility lines.
Red Maple,
Acer rubrum
Uses: Lawn / Street-tree.
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 Uses: Lawn area.
Native maple with yellow-orange fall foliage. Upright cultivars are available
for narrow spaces. Not salt tolerant. See ‘Rocky Mtn Glow’ Sugar Maple for
smaller landscapes in the Small Tree section.
Catalpa,
Catalpa Uses: Lawn area.
White flowers bloom in June and seedpods develop in the Fall. Interesting Winter
form.
Beech,
Fagus Uses: Lawn area.
American and European varieties. 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 americana (White) & pennsylvanica (Green) Uses: ST
/ L
Green and White Ash are large, fast growing shade trees. The Green Ash is more
common and has bright yellow fall foliage. Varieties include ‘Summit’ and
‘Patmore.’ The White Ash varieties ‘Autumn Purple’ and ‘Empire’, is a new
upright selection. ‘Leprechaun’ Ash* is a small 15’ round shaped tree for
smaller areas. (Emerald Ash Borer is a serious potential threat to Ash trees,
not in Maine, yet.)
Ginkgo, Ginkgo biloba
Uses: 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.
Cultivars: ‘Autumn Gold*’ – broad, conical form with good Fall color, ‘Magyar’
upright form.
Tuliptree,
Liriodendron
Uses: ST
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 Uses: Lawn
A large shade-tree magnolia that does not have the showy spring flowers of other
Magnolias. It is an interesting tree, A beautiful specimen is on Brackett Street
at Walker Street.
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’.
Elm,
Ulmus (ST,L) American Elm, Chinese or Lacebark Elm,
Once the most popular of all trees, Dutch Elm Disease (DED)has caused and
continues to be a severe problem. New resistant varieties have shown promise in
resistance to DED, ‘Patriot’, ‘Princeton’, ‘Pioneer’, and ‘Lacebark’ Ulmus
parvifolia. Limited availability. Fast growing.
Zelkova
(ST,L) (ST,L) Medium to Large tree,
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.
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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.
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 specimen 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 located in USDA Plant Hardiness Zone 5 B
Co-Op Nurseries: Trees must be selected from one of the following nurseries:
O’Donal’s Nurseries in Gorham 839-4262 www.odonalsnurseries.com
Skillin’s Nurseries in Falmouth 781-3860 www.skillins.com
Risbara’s Greenhouse in Portland 797-0066 www.risbarasgreenhouse.com
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