Healthy elm tree

Dutch elm disease poses a significant threat to Edmonton's inventory of disease-free elm trees.


From April 1 to September 30, it is illegal to prune elm trees as per the Community Standards Bylaw 14600 . This ban on pruning helps to prevent the spread of Dutch elm disease.

Be on the lookout for elm leaves that turn yellow during the summer.

What Is Dutch Elm Disease

Dutch elm disease (DED) is a deadly disease caused by a fungus (Ophiostoma ulmi) that can affect any elm tree. Since its introduction from Europe about 1930, it has destroyed millions of American elm trees across North America.

Edmonton has one of the largest concentrations of uninfected American elms in the world. An isolated case of DED was discovered in Wainwright, Alberta in 1998 and two trees in Lethbridge, Alberta tested positive in 2020.

The Problem

Although Alberta is still disease-free, the beetles, which carry the disease, have been found in Edmonton and St. Albert (since 1995), Calgary (since 1994), and Vauxhall (since 1996). Since then, they’ve been found across the province, from Medicine Hat to Grande Prairie.

In other areas, DED arrived three to seven years after the first detection of elm bark beetles. Therefore, the City of Edmonton is investing in a preventative strategy to protect one of the world's last stands of healthy elms.