ASK THE EXPERTS

Q - Native trees in our landscape have witch’s broom. Will this kill our trees?

A - “Witch’s broom” is a term given to a proliferation of dense twig growth that has been associated with the presence of mites, but the cause of the problem is still unclear, says Cathy Rymer, certified arborist and city of Chandler water conservation coordinator. The blue palo verde and foothill palo verde (also called littleleaf palo verde) seem to be most affected by this disorder. This problem is largely cosmetic and, while it can diminish overall vigor, will not kill the tree. Sometimes the weight of the witch’s broom growth can make branches more vulnerable to breakage. Removal of affected branches is the only method of control to date, but may not prevent reoccurrence.