Witch's broom
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; sometimes caused by pathogens
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.
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.
Causes
A tree's characteristic shape, or habit, is in part the product of auxins, hormones that control the growth of secondary apices. The growth of an offshoot is limited by the auxin, while that of the parent branch is not. In cases of witch's broom, the normal hierarchy of buds is interrupted, and apices grow indiscriminately. This can be caused by cytokinin, a phytohormone that interferes with growth regulation. The phenomenon can also be caused by other organisms, including fungi, oomycetes, insects, mites, nematodes, phytoplasmas, and viruses. The broom growths may last for many years, typically for the life of the host plant.
This brief starts where responsible research should: with the source description of “Witch's broom” as 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; sometimes caused by pathogens. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the science & nature register because the source frames it as 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; sometimes caused by pathogens. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated May 13, 2026. The linked authority identifier is Q755981. None of the 0 selected statements returned an explicit reference.
A general summary may omit uncertainty, sample limits or methodological disagreement that is explicit in the technical record. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Witch's broom” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.