In September 2024, the CSU Extension in Jefferson County confirmed its first case of Emerald Ash (EAB) in a small area in central Lakewood. If not treated, EAB will kill green and white Ash since they have no immunity. It will also kill Autumn Purple Ash. Mountain ash is not affected since it is not actual ash trees.
The borer arrived in Colorado in 2013 when an arborist found it near the University of Colorado in Ash trees. Since then, the beetles have spread to Adams, Arapahoe, Boulder, Broomfield, Larimer, and now Jefferson counties. It was just a matter of time before the beetle arrived in Lakewood since it jumped from Arvada over the city to land in Centennial last year.
The first thing Lakewood homeowners notice about Ash trees affected by EAB is canopy thinning and dieback. The trees look sick and lack vigor. If they look closely, property owners will see distinctive D-shaped exit holes in the bark. There may also be heavy woodpecker activity around affected trees. However, by this time, trees are not salvageable and need removal, which is why people need to be proactive in protecting their Ash. For more information on EAB, please click here to view the Ross Tree Emerald Ash Borer Handbook.
Proactive EAB Treatment Is Best Tact
Compared to cities east of the Mississippi, Denver and other Front Range city foresters have had eleven years to treat high-value Ash in the parks and right-of-ways. Lakewood has prioritized ash tree insecticide treatment and removal for several years by removing unhealthy or poorly located Ash and planting other tree species. Learn about Lakewood’s Emerald Ash Borers efforts by visiting Lakewood.org/Invasive-Insects.
Lakewood City’s foresters expect homeowners to be proactive in managing their yard Ash. They should contact a company like Ross Tree to understand their Ash tree treatment options. Ross Tree has three certified arborists and three Qualified Supervisors licensed by the Colorado Department of Agriculture to handle tree insect pesticides. Do It Yourselfer’s word must be getting out because it is getting harder to find EAB drenches with Imidacloprid on the shelves at Home Depot and other hardware stores. These products work for smaller trees and must be applied annually. However, large Ash needs professional treatment.
The Ross Tree offers tree watering, fertilization, and systemic injections to keep Ash trees healthy and resistant to the EAB. Click here to request tree service or call 303-871-9121 for an appointment. We are at your service.