Witches' Broom
Taphrina wiesneri
195 host plants
When you spot abnormal branch growth that resembles a broom or bird's nest on cherry, hazelnut, or juniper in the Puget Sound region, you're likely seeing witches' broom. The infected branch produces many short, slender twigs packed densely together, creating a distinctive dense tuft that stands out against normal branching patterns. These brooms rarely set fruit and have fewer flowers than healthy branches. The base of the broom is swollen and thicker than the normal branch, making it easy to trace where the infection begins.
This disease is incurable once established in a branch, so your only real option is removal. Trace the main stem of the broom back to where it emerges from the normal branch, then cut at least 12 inches below that point to remove all infected tissue. Make the cut into healthy wood to prevent regrowth from an infected stump. Pruning out brooms early before they spread to new branches keeps the problem manageable and preserves tree structure and fruit production.