Friday, November 6, 2015

Prune your elm trees between Oct. 1 and March 31 to prevent the spread of Dutch elm disease

It is a great time to get out and check any elm trees on your property. Did you know you can only prune elm trees between October and March? A provincial pruning ban exists between April 1 and Sept. 30 to discourage pruning elm trees at the wrong time.

This is to help prevent the spread of Dutch elm disease. Dutch elm disease is spread by elm bark beetles attracted to the freshly pruned trees. Pruning when these beetles are not active helps reduce the risk of your tree attracting beetles and getting the disease.

Here are a few tips to help care for your elm trees:
  • Elm materials should be disposed of at City landfills – stored elm firewood is an ideal breeding ground for elm bark beetles.
  • In the fall before freezing, remember to water your trees, and during the spring and summer all trees should be watered every two to three weeks from April to mid-August. Trees need much more water than lawns do. 
  • Ensure your trees are mulched properly. Mulch should be applied no deeper than four inches, not applied against the trunk of the tree (four inches away) and spread out as far as permitted. Mulch adds nutrients to the soil, conserves moisture and regulates soil temperatures. All good things for roots. 
  • And remember, prune your trees ONLY between Oct. 1 and March 31 when the beetle that spreads the disease is not active. 
Keep your trees free of DED

Since Dutch elm disease (DED) was first introduced to North America from Europe in 1930, it has destroyed millions of elm trees. Alberta is one of the last geographic areas in North America to be free of DED and we want to keep it that way. Elm trees are also one of the few types of shade trees that grow in Calgary so it is important to protect them.

For more information on helping your trees visit or view one of our other videos on tree health.

Submitted by Althea Livingston, Parks

No comments:

Post a Comment