plant disorder characterized by a shortening of the internodes and a proliferation of terminal shoots forming a dense. brush-like mass of twigs.

witch's broom (Wikipedia)
Not to be confused with Mistletoes, which are not the host plant's own tissue, but parasitic plants growing on the host.
For a broom associated with witches, see Besom.
For the nebula, see Witch's Broom Nebula.

Witch's broom or witches' broom is a deformity in a woody plant, typically a tree, where the natural structure of the plant is changed. A dense mass of shoots grows from a single point, with the resulting structure resembling a broom or a bird's nest. It is sometimes caused by pathogens.

Witch's brooms on downy birch, caused by the fungus Taphrina betulina
Witch's broom on a white pine.
Witch's broom in Yamaska National Park, QC

Diseases with symptoms of witches' broom, caused by phytoplasmas or basidiomycetes, are economically important in a number of crop plants, including the cocoa tree Theobroma cacao, jujube (Ziziphus jujuba) and the timber tree Melia azedarach.

« Back to Glossary Index