Arboretum News

No Such Thing as a “Messy Tree”

Explore alternatives to the most commonly planted tree species.

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Editor’s Note: We’re celebrating our Season of Trees with Tree Tuesday on the Nature Notes blog. Come back each Tuesday for stories exploring the Arboretum’s trees and tree collections.

Shellbark Hickory
The Shellbark Hickory was the first tree planted at the Arboretum in 1957. It was grown at the Horticultural Research Center from seed collected from Peter Gideon’s former orchard in Tonka Bay (about 5 miles north of the Arboretum). Dr. Leon Snyder rescued the tree when it was dug to make space for a new research planting.

By Peter Moe

The arrival of emerald ash borer in Minnesota has re-awakened interest in alternatives to the most commonly planted tree species.  People clearly understand that the best protection from a series of invasive and destructive tree pests is to create a diverse urban forest using many different species. Unfortunately, we sometimes create a major obstacle to this important step by labeling many species as “messy trees.” Common candidates for this label include catalpa, black walnut, butternut, hickories, Kentucky coffeetree and female ginkgos. Other trees that could be in this category include weeping willow, oaks and buckeyes.

Avoiding this large group of trees from planting and only planting the so called “neat” or “low maintenance” species automatically creates a less diverse urban forest. Some of the above species, including Kentucky coffeetree and ginkgo, have no serious pests, and all of the species, except weeping willow and ginkgo, are native to the United States.

Kentucky Coffeetree seed pod
Kentucky coffeetree pod with seeds.

Large seeds or seed pods can be looked at as a negative from a maintenance standpoint,  but they also add much interest as they are grow during the summer and as they persist into the winter months. Ohio buckeye seeds grow in golfball-sized tan fruits during the summer and in fall the fruits split open and reveal glossy brown seeds.  Ripening walnuts and butternuts look like green limes in the trees during the summer and Kentucky coffee tree pods hang on thick, bold branches all winter creating an interesting silhouette against the blue sky.  Catalpa seed pods are striking, foot-long and cigar shaped.

Anyone with an oak tree knows that they drop large numbers of acorns most years but it is amazing how fast the neighborhood squirrels can clean them up.  Hickories and Black Walnuts are another favorite of theirs. Squirrels are just one of dozens of birds, mammals and insects that depend on oaks and other nut trees for much of their food and shelter, and they should be planted much more than they are today.

Some of these little-used tree species have unusual, spectacular or fragrant blooms. Catalpas produce gorgeous clusters of white orchid-like fragrant flowers. Buckeye flower clusters are reminiscent of lilac blooms in a buttery yellow color. 

Buckeye blooms
The Autumn Splendor Buckeye has beautiful blooms. Photo by Maggie Keith.

Willows bother some people because they drop twigs onto the ground, but no other tree can match the graceful form of a mature weeping willow. In addition, they retain green leaves very late into the fall before finally turning color and dropping in a virtual shower of slender leaves.  All of us as children remember searching for pussy willow blooms in the early spring. 

In my own yard, I have planted many of these underused trees including black walnut, shell-bark hickory, shag-bark hickory, swamp white oak, red oak, Autumn Splendor Buckeye and Kentucky Coffeetree and appreciate their unique beauty.  As Minnesotans we should enjoy our theater of seasons and plant diverse tree species that can provide more seasonal interest.

2 comments on “No Such Thing as a “Messy Tree”

  1. Amy Parenteau

    Are Cottonwoods native to Minnesota? They are considered “messy” but I find this species to be delightful.

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