What is Serviceberry Rust and What Should You Do About It?

Around late Spring, we often get a lot of questions about a strange orange fungus appearing on some people’s Serviceberry (Amelanchier canadensis) trees.  At first glance, it looks like something that might deteriorate your tree’s health.  This fungus is referred to as “rust” because of its rusty-orange color.  It is completely harmless to your plant, and is more of an aesthetic concern in addition to making the berries inedible. There are a variety of different “rust” fungi that affect different pairs of trees.

This particular fungus is hosted on juniper and cedar year-round, and the spores will often spread to their spring host, the Serviceberry. The spores can reach up to 100 feet, so the rust might be coming from somewhere outside of your property. It often occurs on Serviceberry during particularly wet springs.

So What Can You Do?

The best thing you can do is harvest your berries as soon as they are ready, before any possible rust develops.  Remove any branches, berries, or leaves that have serviceberry rust on them.  It is also perfectly okay to leave it be for the season!

At Lauren’s Garden Service, we never recommend spraying any type of fungicide on your plants.  These spray often contain harmful chemicals that end up in waterways and can lead to eutrophication.

Hopefully next year we will have a drier Spring!