DescriptionMortar bees are harmless; they are not aggressive and will not attack. They include the wool-carder bee, the mining bee, the hairy-footed flower-bee, the leafcutter bee and the red mason bee. These bees are known as masonry or mortar bees because they like to nest in crevices or holes in masonry. They prefer to stay near walls that receive sunshine for much of the day. Mortar bees use naturally occurring holes in bricks or mortar joints (especially mortar with a high lime or sand content).