In my little-kid world, the block on which I lived was noteworthy for its trees. I liked lombardy poplars’ razzle-dazzle leaves. Gnarly crabapples offered bitty-bouquets for Barbies and rock-hard green “bombs” to hurl during back-yard games. Big, corrugated catalpas dropped hat-sized leaves, frilly white flowers and long, skinny pods to rattle or peel as we dragged ourselves back to school in the fall.
But ask grownups about those same trees, and you would get a different story. You would hear about the mess the catalpas made, the poplars proclivity toward canker, the nuisance of gathering those little green apples. So were they good trees or bad?
“There’s really no such thing as a ‘good’ or ‘bad’ tree,” says Edith Makra, community trees advocate at the Morton Arboretum in Lisle. “Just trees that are more–or less–desirable for use in specific homeowners’ yards.”
Similar to fashion, finding the right tree “fit” for you and your yard requires careful shopping. One size doesn’t fit all. Take American white oak trees for example, says Peter Bristol, curator of woody plants at the Chicago Botanic Gardens.
“A white oak’s a great tree, but it need lots of space and little foot traffic. You’re not going to put one in a tiny lot in Lincoln Park.”
Likewise, “try to grow a red maple in alkaline soil or a crab apple in heavy shade, and you’ll have problems,” says Heather Green, village forester for Oak Lawn. “People frequently choose the wrong species of tree for their yards.”
With baby trees dangling $200 to $1,000-plus price tags, avoiding such errors make good financial sense, too.
“A tree’s success or failure can have a lot to do with how well homeowners match trees to soil, light and environmental conditions,” Makra says.
To help, Midwest tree experts have done a lot of the legwork, translating expert information on the selection and care of trees into easy-to-read reports and charts (see Morton Arboretum’s Web site, www.mortonarb.org, for everything from “Trees Tolerant of Wet Sites” to “Trees that Attract Birds”).
“But you’ve still got to do your own site-specific homework,” says Adam Schwerner, director of horticulture for the Chicago Park District. “What works in your neighbor’s yard, won’t necessarily work in yours.”
Doris Taylor, manager of Morton Arboretum’s plant clinic, advises homeowners “to think way beyond `What’s pretty in the catalog?’ or `What’s blooming at the garden center right now?'”
She says it’s important to focus on site specifics before selecting trees, asking, for example, how much of the back yard are you willing to dedicate to a tree?
“It’s a good idea to send out soil samples from various areas in the yard to determine soil pH, texture and density,” she says. “Measure how much sun you get and how well your soil drains. That’s all going to play into what you can or can’t plant.”
“You’ve also got to factor in overhanging wires, location of street lights, and measure the distance between where you want the tree and where sidewalks, walls and streets are located,” says Bob Benjamin, a horticulture consultant and retired principal forester for the City of Chicago, Department of Streets and Sanitation.
With those facts in hand, rule out trees that need what your yard can’t give them. Trees that are weak-crotched, weak-wooded or are prone to cankers, blight or borers are the more-obvious losers. Invasive species such as white mulberry also are bad choices.
But strong, nicely shaped trees that showcase flowers, fruits or fancy foliage year-round without getting too messy are winners.
Chicago’s tree elite–the urban foresters, plant curators and arborists who supervise what grows here–do have personal favorites. Trees such as the Kentucky coffeetree, katsuratree, hornbeam, bald cypress, Turkish filbert and Japanese tree lilac are mentioned often. All have beautiful shapes, foliage and multiseasonal interest.
They also are much less commonly planted than maples, ashes, locusts and lindens. (Only six tree species account for 86 percent of the Illinois’ urban trees; half are maples)
“You want a mix of tree varieties and ages,” so that no one disease, such as Dutch elm disease, or insect can wipe out a big chunk of a tree’s population, Benjamin says. (Currently, experts are holding off on planting ashes, worried about the threat of the emerald ash borer.)
Another consideration when selecting trees is “remember to research what a tree will look like 10 to 20 years down the road,” Makra says. “A lot of people buy a tree for what it looks like now. That’s like purchasing a puppy and expecting it to stay that way.”
Blue spruce trees are a classic example. Cute little sidewalk-liners when young, spruces can be an overwhelming 60 feet tall and 30 feet wide when mature.
Conversely, some of Makra’s favorite trees–the Kentucky coffeetree, the gingko and some of the new elm selections–are awkward-looking when young but beautiful when mature.
“They’re truly gangly teenagers,” she says. “But you have to be patient and wait for them to grow out of it.”
Scott Jamieson, president and CEO of Chicago’s The Care of Trees, agrees. “The Kentucky coffeetree is a fantastic city tree, with big, ferny, tropical-looking leaves. But when it’s young, it looks like a hatrack–a haunted-house tree sort of look.”
Of course, most homeowners want plants that look good now and later. Small ornamental trees look great now. But most have short life spans. And many–such as cherry trees, some crabapples and plums–aren’t great in heavy shade and are prone to pests, scabs and blight.
That’s why tree experts will steer you toward Japanese and Peking tree lilacs, serviceberries and redbuds, which have fewer problems, are OK with a mix of sun and shade and have longer life spans.
Although it’s not a small ornamental, the katsuratree, with its interesting bark, heart-shaped leaf and pretty, pyramidal shape, is another beauty that looks good from little to big (it can reach 40 feet when mature).
So, how should a homeowner pull all these considerations together to make their picks? Ed Gilman, author of “Trees for Urban and Suburban Landscapes,” suggests combining site specifics with the trees you’ve found that match them on one question-and-answer sheet.
That done, Care of Tree’s Jamieson says it’s important to balance personal preferences and styles with expert advice.
“You’re not going to want to put a tree in your yard that your research shows is absolutely a bad fit for the soil or light conditions, but you might really love a tree that takes a little extra care and handling. So ask yourself: `How much watering, pruning and maintenance am I really willing to do, or am I willing to pay someone else to do?'”
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If you want a: Large, back-yard shade tree
And you have: A city or suburban location with so-so soil and drainage conditions
Instead of planting a: Norway maple, silver maple
Experts say, consider a: Freeman maple or katsuratree
If you want: A large tree with multiseasonal interest or dappled-shade tree
And you have: A city or suburban location, so-so soil and drainage conditions
Instead of a: honeylocust or American elm
Experts say, consider: A hackberry, regal elm, Kentucky coffeetree or bald cypress (if soil isn’t too dry)
If you want a: Medium-size back- or side-yard tree with multiseasonal interest, offering some shade
And you have a: A city or suburban location, so-so soil and drainage conditions, part sun/part shade
Instead of a: magnolia, European birch, littleleaf linden
Experts say, consider a: Japanese tree lilac, American hornbeam, Peking lilac, Turkish filbert
If you want a: Small, ornamental tree
And you have: Mostly sun, part shade, so-so soil and drainage conditions, city or suburban location, small amount of space
Instead of: A cherry, flowering plum, Bradford pear
Consider a: Corneliancherry dogwood, serviceberry, redbud and any one of a large number of crabapples (See www.mortonarb.org for crabapple selection advice.)
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The dirt on dirt
Eighty to 90 percent of the tree failures are caused by problems with the soil, Jamieson says.
Jamieson, president of Chicago’s The Care of Trees, says, “Usually, it’s something about the soil. In urban situations, soil can be virtually dead.”
Soil can be amended, but it’s always best to fit the tree to what you’ve got. That’s why before planting a tree, it’s a good idea to test soil to find out its composition and how well it drains.
A soil’s pH indicates how well nutrients can be absorbed by the tree. Best soils are slightly acid or neutral (pH between 5.5 and 7.2) Aklaline soils (pH above 7.2) make it hard for the tree to suck in needed nutrients.
A soil’s drainage is determined by a number of factors including texture and structure. Chicago’s clay-like soils can have problems draining, which can restrict root development.
The University of Illinois Cooperative Extension Service has a list of facilities that test soil on its Web site at www.urbanext.uiuc.edu/soiltest/. Before using a lab, ask the cost of the test, what tests will be done and what information will be sent.
For a do-it-yourself soil-drainage test, dig a hole 6 to 8 inches across, 18-inches deep, then fill it with water. If water drains in one to two hours, you have good drainage. If water drains within a day, you have moderate drainage. If water takes longer than a day to drain, you have poor drainage.
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Latin lingo
When shopping for trees, come armed with the tree’s Latin name–easy to find in source books or on the Morton Arboretum Web site (www.mortonarb.org). Why?
Because with so many common names for trees, the specific Latin name clears up confusion. Take “white oak,” for example. Peter Bristol, curator for woody plants at the Chicago Botanic Gardens, recommends the American white oak (quercus alba) as a stately choice for the right back yard.
Quite a difference from Australia’s white oak (lagunaria), a seaside plant with seed pods that cause such extreme skin irritation it’s also called the cow itch tree.
Knowing your Latin also helps if you’re looking for a specific cultivar of a tree species, especially common if you’re shopping for a crabapple or magnolia. The cultivars are all listed under the Latin name of the tree species.
— Monica Kass Rogers
