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Take Advantage of the Fall Color Change

As pumpkin spice lattes make their debut at our local coffee shops, so do the colors of fall. The leaves of trees in our parks and backyards are beginning to change from green to yellow, purple and plum – a clear sign that winter will soon be here. 

Ash leaves

Take advantage of these vibrant signs and Be A Smart Ash.  
With the Emerald Ash Borer confirmed in the City of Westminster, directly neighboring the City of Denver to the west, now’s the time to Be A Smart Ash. Use the vibrant fall color change as your guide and get outside; look for the most colorful leaves, then use these telltale identifiers to confirm you’ve found an Ash: 

  • Compound leaves: A simple leaf is defined as a single leaf that has a bud at the base of the leaf stem. Conversely, a compound leaf (the sort you’re looking for) is defined as having more than one leaflet per leaf connecting to a stem that has a bud at its base. Ash tree leaves typically have 5-9 leaflets per leaf. 
  • Opposite branching: By opposite branching, we mean the branches protruding from tree limbs have a mate protruding from the exact opposite side of the same limb. Only ash, maple, dogwood and horse chestnut trees have opposite branching. 
  • Diamond-pattern bark: While this identification method may not be as helpful when it comes to young ash trees (they typically have smoother bark), the bark on more advanced ash trees tends to have distinct diamond patterns. 

Once you’ve confirmed the tree is an Ash tree, make sure you don’t see any pesky green bugs around, or any wavy trail lines or d-shaped holes in the trunk. Multiple visuals can be found here. Hopefully, the tree is healthy, in which case there are multiple options to help keep it that way. 

If the tree is on public property, look for a tag that says “This Ash Is Covered” to know it’s been treated by the City Forestry Department. More information on the city’s treatment and replacement plan can be found at If the tree is on your personal property, check out your next steps here. 

Think you might have an EAB infestation? Take a lot of pictures and contact the City Forester at or 720.913.0651.