Want beautiful trees like in the forest? Stop doing these things, Michigan expert says.

The spring wildflower show is at its dazzling peak now at Bendix Woods County Park in New Carlisle as thousands of large white trilliums carpet the rolling wooded terrain. The park’s wildflower hotspot is in its state-dedicated nature preserve, where an abundance of native species thrive.

Part of the fairy-tale tranquility comes from the blossoms, but it’s also from the vibrant green hues of the towering trees and how their powerful trunks connect to the forest floor.

So, how is it that trees grow so wonderfully here while trees in our yards run into fickle problems like fungus and disease?

Some of it is just nature. But a lot is also caused by the silly things we humans do in the name of perfection.

I reached out to “The Tree Doctor,” as he calls himself. David L. Roberts had directed the Plant & Pest Diagnostic Clinic at Michigan State University for 15 years, then worked in research and extension services until he retired in 2018. Now, living near Lansing, he gives expert advice on trees at plantdoctorllc.com.

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He attests that undisturbed native forests do the best job of maintaining themselves.

As Arbor Day approaches on April 29, Roberts offers these things you should stop doing to trees.

∎ Stop nicking tree trunks and roots. This happens when you persistently graze over them with lawn mowers and weed trimmers. Likewise, avoid scraping roots as you plant flowers or build stuff around a tree.

Roberts says this harms the tree’s vascular system, which it needs to transmit nutrients and water to its upper reaches. If the vascular system suffers, he says, you can see leaves wilt.

Cuts on the trunk also invite infections that lead to lethal diseases like Verticillium wilt and Phytophthora collar rot, or bleeding canker.

∎ Don’t make mulch volcanoes. It’s common to see landscaping contractors heap large mounds of mulch in a circle around a tree. Mulch is good, but Roberts says too much is just wrong.

It enables diseases to take hold. And, he says, it stimulates the tree to grow what’s known as girdling roots, most common among maple trees, in which roots grow in a circular or spiral pattern and eventually strangle the trunk.

The right amount of mulch can enhance the tree’s health, Roberts notes. It keeps mowers and trimmers away, for one thing. And a larger mulch circle is better at simulating a forest situation than a small circle, he says.

∎ Don’t use mulch that was made with trees or shrubs that had been killed by the fungus Verticillium. Roberts says the fungus afflicts a range of plants and could spread to the tree and other plants. If a plant has been killed by the fungus, he advises that it’s best to destroy it, for example, by burning it.

The potentially lethal disease Verticillium wilt is rarely a problem in forests, he says. Plants can recover from the disease with the right balance of moisture and fertilizer and a lack of stress.

∎ Hold off on herbicides. Be very careful if you’re applying weed killer near a tree to attain a perfect lawn.  Herbicides that target broadleaf weeds can still have some level of toxicity to trees, causing subtle or dramatic damage, Roberts says.

Don’t use herbicides that contain the chemicals Imazapyr or triclopyr or other broad spectrum vegetation killer “in the vicinity of” trees, he advises. A few examples are Roundup Extended Control, Roundup 365 and Ortho GroundClear.

∎ Don’t let trees have a drinking problem. Roberts can riff on this for a long time because he sees it so often: too much watering. Lawn sprinklers spray water all over the leaves and trunk, keeping them wet for prolonged periods, which can lead to fungal diseases.

Excessive irrigation also keeps a tree from sending its roots deep into the soil, making it loosely anchored and prone to falling.

“Wet wilt” can happen when tree roots are immersed in water. Roberts says roots need oxygen in the soil in order to absorb water.

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On the flip side, he notes, we sometimes worry about a tree when it drops its leaves early, say in summer or in very early fall. But that could well be a survival technique as it responds to severe heat or drought, and Roberts says it may turn out OK in the long run.

He advises: Avoid irrigating before, during or after a rain. Also, if you irrigate in the morning, it will help any dampness on the tree to dry off. Drip irrigation systems do avoid wetting the leaves, but they can still irrigate the tree too much if you’re not careful.

Seeking beauty

∎ Wildflower walk: The Harbor Country Hikers will seek wildflowers at 1 p.m. April 29 on a two-mile, naturalist-led hike at Love Creek County Park, 9292 Huckleberry Road in Berrien Center.

∎ Dunes wildflowers: A ranger will lead a two-hour hike to seek spring wildflowers at 1 p.m. CDT April 29 in the Heron Rookery woods in the Indiana Dunes National Park. Be prepared for muddy conditions. The hike will start from the Heron Rookery’s east parking lot at 1336 N. County Road 600 East, in Michigan City. From U.S. 12 or 20 just west of the city, take County Line Road south of Interstate 94, then go west on County Road 1500 North and then south on County Road 600 East. Park entry fees apply.

∎ Pancakes and Trout Day: Start your day April 29 with whole-grain buckwheat pancakes, sausage and drinks from 7:30 to 11 a.m. at Bonneyville Mill County Park, 53373 County Road 131 near Bristol. Then, in a separate event at Bonneyville, join the park’s “Trout Day” hands-on activities for all ages, including tables with trout information, fly tying demos, trout crafts for kids and other things. Both will be in the Feedlot Shelter, across from the mill. Trout Day is free. The breakfast costs $7 per person, free if 3 or younger. Learn more at www.elkhartcountyparks.org.

∎ Benton Canal cleanup: Help park staff and paddling enthusiasts to clear fallen trees and debris from 10 a.m. to 2 p.m. April 30 from the Benton Canal in River Preserve County Park, one mile south of Goshen, so that it can be paddled. Bring water and work gloves. Snacks will be provided. Registration required at www.elkhartcountyparks.org.

Find columnist Joseph Dits on Facebook at SBTOutdoorAdventures or 574-235-6158 or jdits@sbtinfo.com.

This article originally appeared on South Bend Tribune: Michigan Tree Doctor gives Arbor Day advice Bendix wildflowers bloom