A popular name for the broom-like tufts of branches developed on the silver-fir, birch, cherry, and other trees in consequence of the attack of a uredineous fungus, Peridermium elatinum.(noun)
The Century Dictionary (Public Domain)
Use "witches'-broom" in a sentence
"Brazil used to be one of the top producers of cacao, until a fungus called witches'-broom struck the crop in the late 1980s and devastated the country's industry."
"And, of course, we know on the West Coast you get witches'-broom in the"
"When Mr. Burgart up in Michigan finds out that the limiting factor practically cleans him out, there is this question of bunch disease with witches'-broom resulting from ground deficiency."