Besom brooms are traitionally made of twigs tied to a larger pole and are the broom traditionally associated with witches. As a result of its construction, the besom is rounded instead of flat. The bristles can be made of many materials including, but not limited to straw, herbs, or twigs. Supposedly, an upward pointed besom (bristles up), especially over or near a doorway, will help protect the house from evil spirits or negative energies.