When recommending a tree to plant, we go by the guideline, “Right tree, right place”. Many tree species are well suited to the right setting, but there are a few trees that we don’t recommend anywhere. Some of these trees are listed on the Nuisance Tree Lists of several local municipalities. The English Holly, seen above, is considered invasive and is on the Nuisance or Invasive Tree List of all three cities below.
So, what gets a tree on the nuisance list?
• Some are considered a bad choice because of susceptibility to disease and pests in our particular climate here in the Pacific Northwest
• Some spread into restored natural areas, undoing expensive and time-consuming restoration projects
• Some lift up sidewalks with their shallow roots, leading to costly concrete repairs
• Some drop debris, causing tripping hazards or clogging storm drains
• There are just too many of that species already
• Some displace native species by outcompeting
For example, the Norway maple, beloved for its fall colors, was once a favorite street tree, but is now found on several nuisance lists. This European native spreads into natural areas with its drifting seed pods, has shallow roots that can cause sidewalks to buckle, and is over-represented among trees in the urban environment.
Where you have room for new trees, we would be happy to recommend alternatives that would be suitable for your yard or parking strip. We can help you protect your investment with proper structural pruning to help ensure that your trees have a long, healthy life. For a free tree care estimate, please call 503-515-9520.