The drought’s taking a toll on our landscape, but what about those native plants that love this weather? Here are some hearty varieties of reliable trees that love our wild Midwestern weather.
Many plants are struggling with, or have already succumbed to, the double whammy of drought and high heat doled out by Mother Nature this year. No matter how much we water the pretty annuals in our gardens, they just don’t have their usual verve. But what about those plucky native plants? Coneflowers, black-eyed Susans, prairie grasses, spiderwort, bergamot and the like seem to be their usual hale and hearty selves.
While they would undoubtedly appreciate some watering, native plants adapted to our climate long before we came along, and developed defense systems to better handle nature’s extremes.
So it is with trees. Some deal with stress better than others, and those with long ancestry in our climate stand a better chance. Lucky for us, the Midwest is home to a long list of native trees, as well as many non-natives with a long record of doing well here.
“I like a plant you don’t have to baby,” says Jon Carlson, owner of J. Carlson Growers, 8938 Newburg Road, Rockford. “Some trees are tougher than others. Some make less work than others, and some resist pests and disease better. Those are the trees we like to grow and recommend.”
Here’s a list of Carlson’s 10 favorite shade trees, with a few ornamental trees thrown in for good measure. They’re listed in no particular order, and he emphasizes that his list of today’s favorites “may change by tomorrow. There are a lot of good trees in the world.”
“Burr oaks are natives to the region, massive in size, slow-growing and have a picturesque shape with stout branches,” says Carlson. “Red oaks are trouble-free, fast growers that offer nice fall color. White oaks are the finest of all our native oaks, slow to grow, but very majestic-looking. The Scarlet Oak is more tolerant of Midwest soils than some oaks, and won’t develop chlorosis [insufficient chlorophyll] like Pin Oaks can.” For areas that often have wet soil, a swamp oak is a good choice. Carlson also sells Sawtooth, Japanese White, Chinkapin and Columnar English oaks, each with specific advantages. The Shingle Oak, a Midwest native, has shiny, oblong leaves that turn yellow to russet in fall.
Carlson loves beech trees, especially the American Beech, with its beautiful gray bark, towering heights of up to 100 feet, 70-foot wingspan and small, glossy, bright-green leaves. Animals that feed on nuts, like opossums, deer, rabbits, squirrels, flying foxes and porcupines, love it, too. Although it’s native to the southern and eastern U.S., it does very well in the Midwest. Unlike many trees, much of the root system grows on the soil surface, which makes it a poor candidate for urban streetscapes. Carlson sells about a dozen other forms of beech, too, including Weeping Purple Beech, with its mushroom shape, and Blue Beech, which stays in a nice 20- to 25-foot height range.
This fast-growing native can grow to 100 feet and has handsome gray, deeply fissured bark. It sheds leaves early in fall and is late to leaf out in spring, but is largely trouble-free. A member of the legume family, its pods are toxic to people and livestock, if eaten. “Kentucky Coffeetrees are very sturdy but kind of bony-looking when they’re young,” says Carlson. “They’re very urban tolerant, though.”
“This wonderful tree is under-planted,” says Carlson. “I’d like to see them more often in the landscape.” The medium-sized tree has leaves that emerge bright red, change to a blue-green in the summer and show a variety of attractive fall colors. Carlson says the weeping form “has graceful, weeping branches that sort of look like blue-green water cascading over rocks.”
About 150 million years old, the gingko tree is not a native of the American Midwest, but has existed here successfully for centuries, having no known pest or disease issues. “These are very dependable, interesting, low-maintenance trees,” says Carlson. “They have small, fan-shaped leaves that aren’t a big problem to manage come fall, and they tend to drop all their leaves at once.” He only sells male selections, since female ginkgos can produce a bad-smelling fruit. Sizes range from the 50-foot Autumn Gold ginkgo to a 20-foot Weeping Ginkgo, and Carlson also offers a 3-by-3-foot Troll Ginkgo for small spaces. He notes that ginkgos are often planted in urban settings, including downtown Rockford, because they can handle most anything.
“A lot of people still remember the loss of trees around the Rockford area when Dutch Elm Disease came through, back in the 1960s,” says Carlson. “But there are hybrid elms that have very good disease resistance now.” He sells the Accolade Elm, a majestic sort of tree that reaches 70 feet tall, has glossy foliage and a nice vase shape. “When these are planted in a row, alongside a roadway, their shape and crowning make for a nice valley feeling below.”
Among ornamental specimen trees, Carlson finds redbuds to be dependable and loaded with attributes. “Redbuds are just a great native tree, very well adapted to life in our region, which is why you sometimes see them alongside wooded roadsides,” he says. Eastern Redbud stays under 20 feet tall, and has bright, rosy pink flowers all along the stems in early spring. Carlson also sells a weeping form, the Covey Redbud, which has a very graceful form and tops out at about 8 feet.
The ornamental tree form of serviceberry offers something in every season, including food for wildlife. It has white flowers in early spring, cheery red fruit in summer, spectacular foliage color in fall and a pleasing, vase-like form in winter. Carlson also recommends a newer form, called Robin Hill Serviceberry, with lovely pink spring blooms.
“This tree is tried and true, and people really have good luck with it.” These are a good choice for people who want trees airy enough in form that they don’t totally block views or sunlight. Serviceberries thrive in many cold climates, including Eastern Canada and the Netherlands, so our winters pose no threat; summer heat doesn’t faze them, either.
“My favorite among birches is the Whitespire, which is beautiful and much sturdier than many,” says Carlson. “Nothing seems to bother them. They’re less finicky than some birches. I’m not hot on river birches, because they’re prone to a problem of leaves turning yellow and dropping, and that’s hard to correct.”
“These are attractive trees with nice shaggy bark, and wildlife love them for their nuts,” says Carlson. “But they’re hard to transplant, because they have huge root systems and relatively small tops.”
Of course, there are many other good trees that belong on a recommendation list, “like maples, but those already tend to be overplanted,” says Carlson. “We all love the look of weeping willows, but they’re brittle, so unless they’re planted out in a big pasture, you’ll likely spend time picking up after them.”
Not recommended by Carlson, because they’re problem-prone, are boxelder, basswood and most linden trees. “The exception is American Linden, which has much larger leaves and isn’t nearly so prone to bug problems,” he says. “Don’t plant black walnuts if you don’t want a lot of nuts on the ground that can be toxic to grass. And avoid ash trees, of course, because of the emerald ash borer crisis.”
Morton Arboretum, in Lisle, Ill., also recommends avoiding black locust, black cherry, choke cherry, dotted hawthorn, eastern cottonwood, pin cherry and Washington hawthorn, because they have messy fruit/thorns, or pests/diseases vulnerabilities.
Trees Need Watering, Too, During Drought
Even though trees don’t wilt as obviously as small plants do, drought and heat can be hard on them. According to the University of Illinois Extension, more than 90 percent of a tree’s root system is within the top 12 to 15 inches of soil. Few water-absorbing roots are located near the trunk or even under the canopy of trees and shrubs. The hair roots, which take in the water, are located at the plant’s drip-line – the outermost branches – and beyond.
The Extension recommends an every-other-week watering schedule for trees during periods of high heat and drought. Apply water at a tree’s drip-line, not its trunk, and slowly enough so water soaks into the ground rather than running elsewhere. Most trees need at least 1 to 2 inches of water every two weeks. To measure water, place an empty 1-inch can, like a tuna or cat food can, near the dripline. Water until you’ve filled it twice. Another way to test watering depth, according to the Extension, is to stick a metal rod into the soil to see if it’s moist at least 12 to 15 inches deep.
A plain old garden sprinkler is the best tool for watering, and will probably need to run for 90 to 120 minutes. Soaker hoses don’t emit enough water for trees, unless left on overnight.
Certain trees need much more water – about 3 inches per week, when temperatures are consistently above 90 degrees. Water-loving trees include birches, alders, poplars, tulip trees, pin oaks and silver maples. Resist the temptation to water foliage, since this fosters disease, and water early in the morning to reduce evaporation.
Shrubs need watering every two days – more, in the case of water-lovers like hydrangea.
While it may be tempting to focus on watering pretty annual plants rather than trees, the Extension reminds homeowners that trees and shrubs are much more costly and time-consuming to replace.