Trees Not to Plant - Headache Trees

Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent  

There are no truly “bad” trees,  just bad or unwise places to plant them. Trees are often categorized as “bad” because they are too big for the average home landscape; too messy, requiring extra maintenance; too prone to troublesome insects and diseases; or too likely to create other serious problems for the owner.

While there are no bad trees, there are certainly some trees that cause headaches. The problem with headache trees is that they can’t be cured with aspirin.  The best bet is to avoid these trees and the problems associated with them by not planting them in the home landscape.  Let me tell you about the trees that cause the biggest headaches for homeowners.

Sycamore: This is a BIG tree.  It grows to a height of 100 to 150 feet with a spread of equal proportions.  This is just too big for the average home landscape.  In addition to it’s gargantuan proportions, it drops an over abundance of large leaves in the fall.  These leaves, along with the twigs and seed balls dropped throughout the year, create migraines for sycamore owners and their neighbors. 

Another serious problem with sycamores is their predisposition to attack by a fungus disease, sycamore anthracnose or “blight.”  Infections by this disease occur during cool, wet spring weather.  It attacks buds, leaves, and twigs and often leads to the death of buds or the severe loss of leaves early in the season. Twig dieback is also associated with repeated infections. 

Springtime infections from sycamore blight are common in our region. While the disease seldom kills a tree, it does create ugly and unsightly specimens. There are fungicide sprays for control that can be applied just before the buds open in the spring, but this is costly. Fungicide applications will have limited effectiveness unless good coverage of the entire crown is achieved... a difficult feat on giant trees.

Powdery mildew is another fungus disease that has been increasingly common on sycamores in this region.  This disease attacks leaves late in the summer and prevents proper development of new leaves.  Because it happens late enough in the season, it’s generally not considered very damaging.  The sycamore lacebug is another pest problem that has just started appearing on local sycamores.  This insect pest sucks sap from the undersides of leaves and excretes the excess, leaving surfaces below the tree spotted and sticky. Heavily infested leaves become yellow stippled and brown.

The best feature of the sycamore tree is its flaking bark, which creates a beautiful mosaic pattern of greens, silvery gray, and cream.  This pattern is a delight, especially in the winter.  There are also some new cultivars (Bloodgood, Liberty, Liberty, Yarwood) of sycamore that are resistant to anthracnose, but they still grow to be very big trees.  It’s best to plant sycamores in parks or on golf courses where they can grow to stately heights without causing problems.

Silver Maple: Another tree that causes headaches for its owners is the silver maple. This tree was planted early in our region’s history because it was easy to grow; it withstood the harsh climatic and soil conditions; and it grew fast.  It’s the tree’s fast growth and eventual large size that make it a pain.  Silver maples grow almost as large as sycamores, reaching an average mature size of 70 feet.  However, they can reach the heights of 100 feet or more.  Their spread is about two thirds the height.

It definitely is a rapid grower... growing to 10 to 12 feet in five years.  However, the price of fast growth for most types of trees is weak wood and the silver maple is no exception.  The silver maple is prone to breakage from wind, ice, and snow.  It’s soft wood is also prone to wood decay which gets started from broken branch ends and bad pruning cuts.  It’s predilection to wood rot often renders it structurally unsound and hazardous.

The massive root system of the silver maple is the cause of many headaches for its owners.  Its roots are notorious for buckling sidewalks, undermining driveways, and unsettling foundations.  You can see a “good” example of this problem along Kennewick Avenue close to downtown.

There is a long list of potential insects and disease that will attack silver maples, but aphids, boxelder bugs, and verticillium wilt are its major pests in this region.  The boxelder bugs feed on the seeds and don’t actually harm the tree, but the large number of bugs attracted to the seeds can be a real nuisance to tree owners and their neighbors.

These isn’t much that’s desirable about the silver maples except for its fast growth and it’s ability to grow in tough situations. Unlike many of the other members of the maple family, it has poor fall color, turning only a yellow green to brown in the autumn.

The Poplar Family: It’s unusual to defame an entire tree family, but most poplars and cottonwoods cause their owners’ temples to throb. One member of the family is the white cottonwood. To be honest, I like the white cottonwood very much... in someone else’s yard.  The leaves of the white cottonwood are dark green on top and white beneath.  When they flutter in the wind they are a delight to behold.  However, once again we are dealing with a large, fast growing, weak wooded tree with extremely vigorous, invasive roots.  The roots will easily clog sewer pipes, septic systems, and water channels.  The tree is also quite weedy, producing abundant suckers from the roots.  It’s these suckers that frustrate owners and often lead to the tree’s eventual removal.

Eastern cottonwoods are cursed every spring by area residents when the “cotton” or fluff from their female flowers blankets the area.  In addition to this messy cotton, the trees regularly drop leaves, twigs, and even branches.  Again... they’re big, fast growing trees with weak wood and invasive roots.  The mature height of the eastern cottonwood is 75 to 100 feet with a spread one half to three quarters of the height.