|witches' broom in hackberry|
Bare winter branches are ideal for hunting down anomalies like witches' broom. These are deformities seen in woody plants in which a pest or disease triggers a disruption in normal cell growth. Witches' broom commonly seen in hackberrys (Celtis occidentalis) is caused by a mite, whereas witch's broom in honeysuckle (Lonicera), another common "victim," is caused by an aphid, and rust fungus can affect pines.
These abnormal growths are not damaging to the plant, merely unsightly. The best remedy, if you're bothered by the appearance, is to prune them out. But they're not always a bad thing! Several ornamental pine cultivars, such as St. Mary's Broom (Picea pungens 'Saint Mary') originated as witches' broom.
|a smaller witches' broom in the same tree|