The worst trees to plant in your garden

Greetings, dear readers! Andrew here, your friendly neighborhood gardening guru. As breathtaking and beneficial as trees can be, the wrong tree in the wrong place can wreak havoc on your garden and beyond. Join me as we delve into some of the worst tree choices for landscapes and gardens, mainly focusing on potential issues in our beloved home state of Wisconsin.

Before we dive in, let’s consider why thoughtful tree selection matters. Trees are long-term additions to outdoor space, so choosing unwisely can create unforeseen problems for decades. The mature size, root patterns, branch structure, and other traits of trees directly impact how well they fit into your garden or property. Other factors like messiness, invasiveness, and even legal regulations are also essential to weigh.

By understanding the downsides of certain tree species, we can make informed choices and prevent problems later. Now, let’s explore some prime offenders regarding problematic garden trees.

Rooting Out the Problems: Trees with Invasive Roots

A tree’s extensive root system is the key to its survival, but some trees are notorious for their aggressive roots that damage infrastructure, foundations, and pipes. Let’s meet the foundation wreckers and the sidewalk crackers.

The Foundation Wreckers: Trees with Aggressive Roots

While most trees have lateral roots that spread out to anchor the tree, some species take this to the extreme. I advise avoiding the following trees with vigorous, invasive roots that greedily seek out water and nutrients:

• Silver Maple (Acer saccharinum) – With roots that snake over 100 feet from the trunk, silver maples easily damage sidewalks, driveways, sewer lines, and building foundations.
• Cottonwood (Populus deltoides) – The cottonwood’s thirsty taproot and spreading laterals readily invade pipes and concrete.
• Willow Trees (Salix spp.) – Willows aren’t called “water-seekers” for nothing! Their root systems contain both deep taproots and invasive laterals that wreak havoc.

Homeowner horror stories abound of tree roots run amok. One client had to remove their front-yard silver maple after its roots cracked the sidewalk and clogged the sewer lines repeatedly. Another battled constantly with the cottonwood roots snaking into their basement and choking the pipes.

Cracking Up: Trees That Damage Concrete and Pipes

In addition to the heavy hitters above, these trees deserve a spot on the sidewalk cracker most-wanted list thanks to their pipe-clogging and concrete-cracking prowess:

• Oak Trees (Quercus spp.): With taproots that plunge over 20 feet down and anchoring laterals spreading over 100 feet out, oak tree roots jostle with sidewalks, driveways, and plumbing.
• Elm Trees (Ulmus spp.) – Elm trees may grace parks and public spaces, but their robust root systems don’t belong near concrete or pipes.
• Poplar Trees (Populus spp.): Members of the poplar family, like aspen and cottonwood, love to establish themselves underground, disrupting infrastructure in their path.

If you want to avoid continuous pipe repairs or sidewalk replacements, steer clear of these troublemakers or plant them a significant distance from any hardscaping or plumbing. Tree root barriers can also be installed as a preventative measure.

Consider cherry, crabapple, dogwood, or Japanese maple trees for low-maintenance options less likely to disturb infrastructure. Their roots tend to be less invasive, making them easier neighbors.

Seed of Chaos: Messy Trees Not to Plant

Beyond infrastructure damage, some trees create serious messes with fruit, flowers, sap, and foliage. Let’s discuss the litterbugs and sticky trees best avoided.

Leaves of Labor: Deciduous Trees That Demand Clean-Up

While all deciduous trees shed their leaves in autumn, some drop copious amounts of foliage that require tireless raking. To avoid creating a slippery, soggy mess in your yard, prevent these leaf-shedding champions:

• Maple Trees – Gorgeous fall color comes at a price, with maple leaves blanketing every surface.
• Oak Trees – In addition to leaves, acorns create headache-inducing litter.
• Elm Trees – Elms drop thousands of tiny leaves that multiply when raking.
• Poplar Trees – Aspen, cottonwood, and other poplars drop leaves by the truckload.

If you prefer lower-maintenance options, consider evergreen trees like spruce, fir, pine, arborvitae, or hemlock that don’t lose their leaves. Opt for smaller-leafed trees like cherry, crabapple, dogwood, or Japanese maple for moderate litter.

Sticky Situations: Sap-Dropping Trees to Avoid

Nothing ruins a paint job or pavement faster than excessive sap. To avoid tacky messes, avoid these sappy offenders:

• Pine Trees – Pine sap may smell divine but drips and sticks with a vengeance.
• Spruce Trees – Spruces produce copious sap that coats every surface it touches.
• Fir Trees: Fir sap may not seem sticky initially, but it quickly bonds with cars, patios, and clothing.

Rather than risking sticky vehicles or shoes, choose trees with minimal sap. Excellent sap-free options include many deciduous species like maple, oak, elm, and dogwood. Fruit trees like apples, cherries, peaches, and pears are also sap-free. Opt for magnolias, crabapples, lilacs, or redbuds for colorful blossoms without the sap.

Water Guzzlers: Trees with High Water Demand

In addition to structural damage and messy droppings, some trees are downright greedy regarding water usage. Let’s review the thirstiest trees, which can skyrocket your water bills.

Thirsty Giants: Trees That Can Skyrocket Water Bills

When selecting a tree, it’s easy to underestimate how much water it will require once fully mature. To avoid draining your wallet and water supplies, prevent these high-maintenance water guzzlers:

• Willow Trees (Salix spp.) – Willows live up to their reputation, slurping over 100 gallons of water daily in hot weather.
• Cottonwood Trees (Populus deltoides): A mature cottonwood can drink up to 200 gallons daily, so its placement warrants careful consideration.
• Silver Maple Trees (Acer saccharinum) – Fast-growing silver maples need ample moisture, consuming up to 100 gallons daily.
• Sweetgum Trees (Liquidambar styraciflua) – Sweetgums demand high irrigation to support their quick growth and broad leaves.

Select drought-resistant trees adapted to Wisconsin’s extreme climate to save on water bills. Try hardy native options like oak, pine, bald cypress, viburnum, or elderberry. Once established, non-native choices like olive, honeylocust, ginkgo, and Japanese zelkova thrive on little water.

Uninvited Guests: Trees That Attract Pests

Moving down the list of problematic trees, let’s discuss those that invite an insect convention to your yard.

Bug Beacon: Trees That Lure Unwanted Insects

A few trees have the dubious honor of attracting every bug in the neighborhood. To avoid providing an open buffet for pests, steer clear of:

• Tree of Heaven (Ailanthus altissima) – Palatable to over 40 insect species, from aphids to beetles.
• Apple trees (Malus spp.) are beloved by aphids, leafhoppers, apple maggots, and codling moth caterpillars.
• Ash Trees (Fraxinus spp.) – Ash borer beetles and aphids relish their share of ash trees.
• Basswood/Linden Trees (Tilia spp.) – Aphids and Japanese beetles exploit the basswood’s hospitality.
• Birch Trees (Betula spp.) – Birch leafminers and bronze birch borers thrive on birch leaves and bark.
• Elm Trees (Ulmus spp.) – Elm leaf beetles, elm cockscomb galls, and the Dutch elm disease fungus plague elms.
• Oak Trees (Quercus spp.) – Over 500 insect species dine on oak trees, especially caterpillars and beetles.

To avoid hosting an insect convention in your yard all summer, choose trees less prone to infestations, like dogwood, redbud, magnolia, juniper, spruce, or hemlock. Also, practice preventative care through pruning, fertilization, pest monitoring, natural pest deterrents, and diversity. An integrated pest management approach minimizes reliance on pesticides.

Allergy Alert: Trees That May Exacerbate Allergies

In addition to pest pandemonium, some trees wreak havoc for allergy sufferers by releasing copious amounts of pollen. Let’s identify the worst sneeze-inducing trees.

Sneeze Trees: Common Allergenic Flora

For those cursed with tree pollen allergies, steer clear of these infamous allergic offenders:

• Olive Trees (Olea europaea) – Prized for its fruit, olive pollen is also robust and allergenic for many people.
• Elm Trees (Ulmus spp.) – Elm pollen blankets the air in early spring, triggering allergic reactions.
• Birch Trees (Betula spp.) – Elegant birches produce copious allergy-inducing pollen in spring.
• Maple Trees (Acer spp.) – Maple flowers release abundant allergy-aggravating pollen.
• Oak Trees (Quercus spp.) – Oaks bombard the air with allergy-provoking pollen in spring.

Plant low-pollen trees like dogwood, hawthorn, willow, pine, spruce, magnolia, holly, pear, or plum to avoid misery during allergy season. Female ginkgo and yew trees produce no pollen at all. Also, consider allergy-friendly flowering trees like fringe, serviceberry, styrax, and star magnolia. With thoughtful selection, you can craft an allergy-free oasis.

The Non-Natives: Invasive Tree Species to Be Wary Of

Beyond aggravating allergies, some notoriously aggressive trees muscle their way into natural areas, damaging ecosystems. Let’s examine these invasive tree troublemakers.

Out of Place: Understanding Invasive Tree Species

Invasive tree species are non-native plants introduced from other continents that outcompete native flora. Growing and spreading rapidly, invasive trees disrupt local ecosystems in the following ways:

• Displace native vegetation, reducing biodiversity.
• Alter habitat conditions and resources.
• Change soil chemistry, light availability, and water cycling.
• Hybridize with native species, diluting their gene pool.

Prolific seed production and abundant growth allow invasives like these to take over:

• Tree of Heaven (Ailanthus altissima) – This rapidly growing Asian native seeds itself prolifically.
• Norway Maple (Acer platanoides) – Norway maples aggressively spread, displacing native maples.
• Russian Olive (Elaeagnus angustifolia) – Russian olives take over riparian areas, threatening willows and cottonwoods.
• Siberian Elm (Ulmus pumila) – Siberian elms invade prairies and fields, suppressing grasses and wildflowers.
• Common & Glossy Buckthorn (Frangula alnus & Rhamnus frangula) – Buckthorns take advantage of forests and edges.

Avoid using known invasives like these in landscapes and gardens. Instead, opt for native trees or non-invasive imports like Kentucky coffeetree, swamp white oak, paper birch, Ohio buckeye, and eastern redbud. Contact your local extension service for recommendations of non-invasive trees suitable for Wisconsin’s varied growing zones.

High-Risk High-Rise: Trees Prone to Storm Damage

In addition to long-term ecosystem impacts, some trees fail dangerously when faced with extreme weather. Let’s examine which tall trees are most likely to topple under stormy circumstances.

When the Wind Blows: Trees That Can’t Stand the Storm

Wisconsin’s seasonal storms mean selecting solid and sturdy trees is crucial, especially in exposed areas. Avoid these high-risk varieties vulnerable to wind and ice damage:

• Silver Maple (Acer saccharinum) – Weak wood and shallow roots make silver maple prone to storm damage.
• Bradford Pear (Pyrus calleryana) – Tight branch forks of Bradford pears split easily in winds.
• Aspen/Poplar (Populus tremuloides) – These slender trees blow over readily in high winds.
• Willow (Salix babylonica) – Weeping willows with pendulous branches readily sustain storm damage.
• American Elm (Ulmus americana) – Dutch elm disease compounds elms’ susceptibility to wind damage.

Instead, choose storm-resistant trees with adaptations like:

• Deep, extensive root systems – Examples: oak, pine, bald cypress
• Dense, strong wood – Examples: hickory, black gum, ironwood
• Broad, spreading canopies – Examples: bur oak, linden, elm
• Moderate height and width – Examples: redbud, crabapple, dogwood

Proper planting, pruning, and care also increase a tree’s chances of surviving severe weather. Assess tree health and trim dead wood regularly.

While on legal matters, let’s turn to tree selection strategies that avoid disputes with neighbors.

Legal Limbs: Trees That Could Land You in Trouble

Properly chosen trees sometimes cross legal boundaries, causing disputes between neighbors. Let’s review tips for choosing neighbor-friendly trees.

Neighborly Nuisance: Trees That Break Boundaries

Well-meaning gardeners sometimes plant fast-growing trees that block views or drop debris on the neighbors’ side. To avoid ending up in legal entanglements down the road:

• Select slow-growing trees that won’t obstruct sightlines as they mature.
• Choose trees that are less likely to invade the property line with roots or branches.
• Opt for trees that don’t produce messy fruits, flowers, or sap.
• Consider ultimate tree height and spread before planting near lot lines.
• Communicate with neighbors before planting new trees along shared boundaries.

You can avoid most tree troubles with neighbors by planning. If disputes do arise, approach the situation in good faith. Start by diplomatically addressing concerns before they escalate. Independent mediation or legal guidance can also help resolve knotty tree dilemmas.

Above all, when it comes to problematic trees, an ounce of prevention is truly worth a pound of cure. We’ve covered the prime offenders to avoid, but what are good choices? Consult reputable garden resources to select the best trees for your specific conditions and goals. With careful selection and attentive care, you can avoid tree troubles and craft a landscape to enjoy for generations.

Until next time, happy gardening! Let me know if you have any other tree tips or questions. I’m constantly branching out to expand my tree knowledge!