Sick Cherry Tree*


Good morning, I live in Milton and we have some fruit tree, apple and cherry trees that are not flowering. I have taken some pictures to see if you can help us. Thank you


Thank you for contacting Toronto Master Gardeners.

Your trees are definitely infected by fungus. All water we have had this spring and summer created the perfect conditions for their development. The picture shows Cedar-Apple Rust (Gymnosporangium juniperivirginianae) which is an interesting disease because it requires a host plant, such as cedar, quince or hawthorn to develop. The fungus develop in large galls or growths found on the host plant. In spring, the galls dry, releasing the spores into the air where they are carried to apple trees. Rust causes yellow or orange spots on the leaves and distorted or mottled fruit.

Cedar-apple rust cannot spread from apple to apple or from red cedar to red cedar – the fungus must go through the two-year life cycle, alternating between hosts.

Rust is unsightly but typically does not kill the plant, although it can weaken it. Good cultural practices that should be effective in getting rid of the rust include:

  • Clear plant debris from around the base of the plant (don’t compost this material – discard in garbage, as rust spores can survive composting)
  • Make sure the soil around the plant has good drainage
  • Pick off affected leaves (if there aren’t many of these) – if you removed huge numbers of leaves, this would affect the plant’s health
  • Prune the plant to ensure good air circulation and light penetration among the leaves.
  • Mulch helps to reduce stress to the plant – a 3-4 inch deep layer around the bush (with a minimum 2 inch space between the mulch and trunk area to permit air circulation)
  • At the end of the growing season, remove all diseased leaves/plant material in case the rust spores survive our winters (again, do not compost this material)
  • When fall comes, add compost to the soil around the plant to provide nutrients for the coming months.

For more information and references:

OMAFRA: Cedar Apple Rust

Missouri Botanical Garden: Cedar Apple Rust