My Serviceberry has some berries that aren’t normal


I was picking some berries for a pie and I picked a couple that almost look like half bur, half berry. The tree gets full sun and it grows in Saint Paul, Minnesota.



Well I am sure that you were incredibly surprised to find this weird permutation to your serviceberry (Amelanchier). Perhaps if you looked closely at the berries you also noticed that they left a red dust. This is one of the fungal diseases that attack members of the large rose family (Rosaceae) including apples and serviceberries, and often happens when there is a damp environment from humid or wet weather. It is a rust problem.

This set of diseases, caused by  Gymnosporangium rust fungi,  is odd because it requires two living plant hosts, planted near one another, in order to complete their life cycles, one plant from the Juniperus family and the other from the Rosaceae. The disease starts with a juniper or eastern red cedar and then affects a plant in the rose family, like apples, hawthorns, pears or in your case the serviceberry.

I found photos of a serviceberry infected with cedar apple rust on this blog so take a look to see if it is what you experienced:

The good news is it probably won’t cause damage to your serviceberry but may require some careful clean-up of infected parts of the plant this season. It also might make people reconsider the pairing of these two families of plants in proximity to one another in their gardens.