Add more valuable bee pollinators to your garden with heavy duty large cedar Mason bee house. These professional-grade Mason bee houses have removable cedar trays for annual cleaning. They are called Mason bees because they work with mud to build & seal their nests. Mason bees are attracted to flowering plants, such as vegetables, fruit trees & bushes, flowering annuals, perennials & vine plants. Their work in the spring can determine the volume of fruit or vegetables that will be available to harvest. Mount to a post or wall ideally near a source of mud. For best results, use near flowering plants known to attract bees (bee Balm, black-eyed Susan, purple coneflower, etc.). The fiberboard nesting tubes should be replaced each Spring after Mason bees have emerged from their nests.