The good, bad, & the ugly

Trees provide us with many environmental, aesthetic, functional and economic benefits. Tree selection is one of the most important considerations when a homeowner, nurserymen or landscaper is deciding what species to grow or plant. Many questions need to be answered including size, location, site characteristics, aesthetic features, pest susceptibility, hardiness and maintenance considerations.  Some trees can become a maintenance headache due to their inherent pest problems or lack of structural integrity. The trees represented in this story have not generally performed well in urban and suburban areas of the Midwest. Some are susceptible to insects and diseases, and some have severe structural problems such as being weak-wooded or prone to girdling roots or included bark formation. Other species have cultural problems such as intolerance to high pH, road salt, drought or poor drainage. Some are invasive.

Some of these trees may do quite well in other parts of the U.S., so my intention is not to apply a blanket statement for all these trees to all situations. Invasiveness and pest susceptibility vary geographically. This article is based on more than 25 years of field experience and data collected from numerous states’ plant disease and insect diagnostic clinics, and conversations with arborists, nurseries, landscapers and extension personnel. There are alternative species that can be used and are mentioned here. These alternative tree species have performed well in USDA Hardiness Zone 4b.

1 Acer platanoides (Norway maple)
Abiotic or structural problems: Poor structure, tight branching, often forms double leaders, girdling roots, shallow root system, leaf scorch, frost crack and sunscald on young trees, intolerant to poor drainage.

Insects and mites: Japanese beetles, cottony maple scale.

Diseases: Verticillium wilt, basal/crown rot near the soil line and decline due to deep planting, Eutypella and Nectria cankers, internal decay when older, root rot.
Invasive? Yes, especially in woods and natural areas due to production of lots of fruit/seed.

2 Fraxinus spp. (ashes)
Abiotic or structural problems: Girdling roots, subject to storm damage, poor form (green ash), often forms double leaders, leaf drop in late spring (green ash), bark splitting, white ash intolerant to poor drainage.

Insects and mites: Emerald ash borer, native ash borers, oystershell scale, ash plant bug, ash flower gall mite, sawflies.

Diseases: Anthracnose, Verticillium wilt, ash yellows, basal rot (white ash) from deep planting, leaf spot, cankers.

3 Tilia cordata, especially ‘Greenspire’
Abiotic or structural problems: Tight branching, often develops multiple leaders, narrow branch crotch angles leads to included bark formation, requires lots of training pruning, basal suckering, girdling roots, subject to storm damage, sunscald on trunk, sensitive to road salt and juglone, leaf scorch, intolerant to poor drainage.

Insects and mites: Japanese beetles love lindens, linden borer, gypsy moth, some leaf galls, spider mites, scale.

Diseases: Basal/crown rot due to deep planting, root rot, Nectria canker, Verticillium wilt, anthracnose.

4 Malus spp. disease susceptible cultivars (flowering crabapple): ‘Indian Summer,’ ‘Profusion,’ ‘Radiant,’ ‘Red Jade,’ ‘Royalty,’ ‘Spring Snow’ are a few examples.

Abiotic or structural problems: Basal suckering from rootstock, watersprouts on branches, poor form and tight branching (some cultivars), sensitive to juglone, intolerant to poor drainage.

Insects and mites: Japanese beetles, spider mites, Eastern tent caterpillar, gypsy moth, aphids, leaf rollers, borers, fall webworm, cankerworms, scale.

Diseases: Susceptibility varies by region; apple scab, frogeye leaf spot, fireblight, cedar-apple rust, powdery mildew, cankers, root rot.

Acer miyabei 'Morton' from Chicagoland Grows, provides excellent pest and disease resistance and is non-invasive.5 Acer saccharinum (silver maple)
Abiotic or structural problems: Poor structural form, narrow branch crotch angles leading to included bark formation, weak-wooded, subject to storm damage, watersprouts on branches, shallow surface roots, girdling roots, aggressive root system, sensitive to juglone, leaf scorch, frost crack and sunscald on young trees, thin bark easily damaged due to mechanical injury.

Insects and mites: Eriophyid gall mites (causes bladder, ermineum and spindle galls), cottony maple scale and other scales, borers.

Diseases: Anthracnose, bacterial wetwood, Verticillium wilt, internal trunk decay, cankers, tar spot, Venturia leaf blotch.

6 White barked birches: Betula papyrifera (paper birch, canoe birch), especially the Renaissance series, B. ‘Varen’ (Prairie Dream), B. pendula (European white birch), B. ‘Madison’ (White Satin), B. ‘Avalzam’ (Avalanche), B. platyphylla (Asian white birch), B. platyphylla var. japonica (Japanese white birch), B. ‘Crimson Frost,’ B. ‘Penci-2’ (Royal Frost), B. utilis var. jacquemontii (white-barked Himalayan birch), B. maximowicziana (Monarch birch), B. populifolia ‘Whitespire’ (Whitespire gray birch, ‘Whitespire Senior’ is less susceptible to borers and is only asexually propagated.)

Abiotic or structural problems: Intolerant to heavy clay soils or poor drainage, road salt and drought intolerant, sensitive to juglone, not heat tolerant, shallow roots, susceptible to storm injury.

Insects and mites: Bronze birch borer, birch leaf miner, Japanese beetles, gypsy moth, sawflies.

Diseases: Anthracnose, cankers, leaf spot.

7 Poplars, willows and their hybrids: Populus deltoides (eastern cottonwood), P. alba (white poplar), Salix × sepulcralis var. chrysocoma (golden weeping willow) and S. matsudana × Salix alba (Austree willow).

Abiotic or structural problems: Weak-wooded, fast growing, susceptible to storm damage, aggressive roots, consistent fruit, leaf, seed and branch litter problems.

Insects and mites: Willow leaf beetle, borers, Japanese beetles (willows), elm sawfly (willows), aphids, fall webworm, gypsy moth, scale.

Diseases: Leaf spot, leaf rust, many stem and trunk cankers, bacterial wetwood, leaf and shoot blight, anthracnose.

8 Some cherries and plums: Prunus virginiana ‘Schubert’ or ‘Canada Red’ (Canada Red chokecherry), P. serotina (black cherry), P. ‘Newport’ (Newport plum), P. nigra ‘Princess Kay’ (Princess Kay Canadian plum), P. padus (European bird cherry), P. pensylvanica (pin cherry, fire cherry), P. americana (American plum, wild plum), P. cerasifera (purpleleaf plum), Prunus × cistena ‘Schmidtcis’ (Big Cis, tree form)

Abiotic or structural problems: Weak-wooded, susceptible to storm injury (black cherry), intolerant to heavy clay/poorly drained soils, short-lived, narrow branch crotch angles leading to included bark formation, girdling roots, leaves, seeds and twigs are poisonous.

Insects and mites: Shothole borers, eastern tent caterpillar, Japanese beetles, scale, fall webworm, pear slug, gypsy moth, cankerworms, spider mites.

Diseases: Very susceptible to black knot, bacterial canker, brown rot, internal decay, viruses, root rot, crown rot, cherry leaf spot, plum pox.

9 Mountainashes: Sorbus aucuparia (European mountainash), S. americana (American mountainash), S. decora (showy mountainash), S. alnifolia (Korean mountainash)

Abiotic or structural problems: Narrow branch crotch angles leading to included bark formation, sunscald on trunk, intolerant to heavy clay/poorly drained soils, not heat tolerant, intolerant to wet soils, road salt, drought and air pollution.

Insects and mites: Mountainash sawfly, borers, leafhoppers, Japanese beetles, aphids, gypsy moth, spider mites, fall webworm, oystershell scale, gall mites.

Diseases: Very susceptible to fireblight, stem cankers, apple scab on fruit and leaves, leaf rust, root rot.

10 Some hawthorns: Crataegus laevigata ‘Crimson Cloud’ (‘Superba’), ‘Paul’s Scarlet’, (Crimson Cloud and Paul’s Scarlet English hawthorns), C. ‘Vaughn’ (Vaughn hawthorn), C. × mordenensis ‘Snowbird’ and ‘Toba’ (Snowbird and Toba Morden hawthorns), C. mollis (downy hawthorn), C. ambigua (Russian hawthorn), and C. punctata ‘Ohio Pioneer’ (Ohio Pioneer thicket or dotted hawthorn)

Abiotic or structural problems: Intolerant to road salt and wet soils, sharp thorns, narrow branch crotch angles leading to included bark formation, fruit on some hawthorns can create a litter mess, difficult to transplant.

Insects and mites: Leaf blotch miner, woolly aphids, lacebugs, borers, gypsy moth, spider mites, scale, aphids.

Diseases: Very susceptible to cedar-apple/hawthorn/quince rust on leaves, twigs and fruit (rust can defoliate the trees by midsummer), fireblight, powdery mildew, leaf spot, leaf blight, stem cankers.

11 Picea pungens (Colorado blue spruce)
Abiotic or structural problems: Sensitive to juglone, intolerant to wet soils, intolerant to heat/pollution/high humidity, short-lived tree.

Insects and mites: Cooley spruce gall adelgids, eastern spruce gall adelgids, spruce budworm, spider mites, borers, spruce bud scale.

Diseases: Cytospora canker, Rhizosphaera needle cast, root rot, Weir’s cushion rust, spruce needle drop, often full of dead branches from diseases.

12 Some pines: P. nigra (Austrian pine) and P. sylvestris (Scots pine, Scotch pine)
Abiotic or structural problems: Sensitive to juglone, intolerant to wet soils, short lived tree due to pests. Scots pine is prone to limb breakage due to snow and ice loads.

Insects and mites: European pine shoot moth, Zimmerman pine moth, European pine sawfly, bark beetles, borers, scale, pine needle scale.

Diseases: Diplodia tip blight, pine wilt nematode, Dothistroma needle blight, Lophodermium needle cast, root rot, brown spot (Scots pine).

13 Juniperus scopulorum (Rocky Mountain juniper)
Abiotic or structural problems: Gets leggy and ratty in shade, not heat tolerant, intolerant to high humidity or poorly drained soils, short-lived tree/shrub due to pests, prone to limb breakage from snow and ice loads.

Insects and mites: Bagworms, spider mites, scale.

Diseases: Very susceptible to Phomopsis tip blight and canker leading to extensive death of branches, cedar- apple/hawthorn/quince rust, root rot, cankers.

Better tree choices for the Midwest
∞ Acer × freemanii
(Freeman maple)
Firefall, First Editions Matador, Celebration, Autumn Fantasy, ‘Marmo,’ ‘Morgan’ (also known as ‘Indian Summer’), Sienna Glen
∞ Acer miyabei (Miyabe maple)
Rugged Ridge, State Street
∞ Acer rubrum (red maple in acidic soils only)
‘Armstrong,’ ‘Autumn Flame,’ ‘Autumn Radiance,’ ‘Autumn Spire,’ First Editions Scarlet Jewell, ‘Bowhall,’ ‘Brandywine,’ Red Sunset, Red Pointe, ‘Karpick,’ Burgundy Belle, ‘New World,’ ‘Northwood,’ Northfire, Rubyfrost, ‘Red Rocket,’ Scarlet Sentinel, ‘Somerset,’ ‘Sun Valley’
∞ Acer saccharum subsp. nigrum (black maple)
‘Fall Red,’ ‘Green Column’
∞ Acer platanoides x A. truncatum
‘JFS-KW202’ Crimson Sunset, Norwegian Sunset, Pacific Sunset
∞ Celtis occidentalis (common hackberry)
 ‘Chicagoland,’ Prairie Sentinel, ‘Prairie Pride’
∞ Corylus colurna (Turkish filbert)
∞ Ginkgo biloba (Ginkgo – male cultivars only)
‘Autumn Gold,’ Golden Colonnade, ‘Magyar,’ Princeton Sentry, ‘Saratoga,’ Presidential Gold
∞ Gleditsia triacanthos var. inermis (thornless honeylocust -- male cultivars)
Halka, Northern Acclaim, Imperial, Shademaster, Skyline, ‘True Shade’
∞ Gymnocladus dioicus (Kentucky coffeetree)
‘Espresso,’ Prairie Titan, ‘Stately Manor’
∞ Phellodendron amurense (Amur corktree – male cultivars only)
‘Macho,’ Eyestopper
∞ Phellodendron sachalinense (Sakhalin corktree)
‘His Majesty’
∞ Platanus × acerifolia
(London plane tree)
Exclamation! (Zone 5)
∞ Quercus bicolor (swamp white oak)
∞ Quercus × bimundorum
Crimson Spire
∞ Quercus imbricaria (shingle oak -- acidic soils only)
∞ Quercus macrocarpa
(bur oak)
Urban Pinnacle
∞ Quercus × macdenielli
Heritage oak
∞ Quercus muehlenbergii
(chinkapin oak)
∞ Quercus palustris (pin oak -- acid soils only)
∞ Quercus robur (English oak)
Skyrocket, Skymaster.
∞ Quercus Rosehill
∞ Quercus × schuettei (swamp bur oak)
∞ Quercus × warei
Regal Prince
∞ Taxodium distichum (baldcypress -- use northern seed provenances)
‘Shawnee Brave’
∞ Tilia americana (American linden -- sensitive to road salt)
Frontyard, ‘Boulevard,’ ‘Continental Appeal,’ Legend, ‘Lincoln,’ American Sentry
∞ Tilia 'Redmond'
∞ Ulmus americana (American elm)
‘Jefferson,’ ‘New Harmony,’ ‘Princeton,’ ‘Valley Forge’
∞ Ulmus hybrids
‘Frontier,’ ‘Homestead,’ Accolade, Triumph, Vanguard, Danada Charm,  Commendation, ‘New Horizon,’ ‘Patriot,’ ‘Pioneer’
∞ Ulmus japonica (Japanese elm)
‘Discovery’
∞ Ulmus wilsoniana
‘Prospector’

Laura G. Jull is associate professor, horticulture; extension specialist, University Wisconsin-Madison, lgjull@wisc.edu.