Mason bees, belonging to the genus Osmia, are highly efficient solitary pollinators that do not produce honey or wax. Unlike social honeybees, these insects do not possess a stinger to defend a hive, making them ideal for backyard gardens and small orchards. A single mason bee can pollinate as many flowers as 100 honeybees in a day, significantly boosting fruit and vegetable yields. This guide provides a practical framework for sourcing, ordering, and preparing for the arrival of these effective garden helpers.
Identifying Reputable Suppliers
The most reliable method for acquiring mason bees is through specialized online retailers who focus exclusively on native pollinators. These suppliers often have established protocols for managing the bee life cycle, ensuring the cocoons are clean and healthy. They provide expertise and quality control beneficial for first-time bee raisers.
Sourcing from a reputable vendor is paramount because it ensures the cocoons are free from common pests and diseases that can decimate a population. Look for suppliers who guarantee their stock is cleaned to remove parasitic organisms, such as the Cacoxenus indagator fly (Houdini fly) or parasitic mites like Chaetodactylus krombeini. Clean cocoons are generally washed in a mild bleach solution during harvesting.
Another reliable option is to check with local garden centers, independent nurseries, or regional bee associations. These sources sometimes carry mason bee cocoons tailored for the local climate, helping ensure you receive the appropriate native species, such as the blue orchard bee (Osmia lignaria). Acquiring locally adapted bees helps guarantee they emerge when local blossoms are ready for pollination.
Understanding the Purchase
When purchasing mason bees, buyers receive them in their dormant, overwintering stage, encased within protective silken cocoons. These cocoons contain the fully developed adult bee, waiting for the correct environmental cue to emerge, making them easy and safe to ship. This method minimizes stress on the insect and allows the new keeper to control the timing of the release.
The optimal time to place an order is typically during the late fall or winter months to secure availability. Shipping logistics are managed by the vendor to align with the local spring bloom period, usually when daytime temperatures consistently reach 50–55°F (10–13°C). This timing ensures the bees emerge when necessary pollen and nectar sources are available.
New keepers generally start with a manageable quantity, such as 50 to 100 cocoons, which is sufficient to pollinate an average backyard garden or small fruit trees. This initial quantity allows the population to establish itself without overwhelming the keeper’s ability to manage the nesting materials and subsequent fall harvest. Suppliers often offer the option to purchase either loose cocoons or cocoons enclosed in a protective emergence box.
Essential Supplies Needed Before Purchase
The successful introduction of mason bees hinges on having a proper nesting habitat prepared before the cocoons arrive. The primary structure is a sturdy, weather-resistant bee house or shelter that protects the nesting materials from rain and predatory birds. This shelter should be mounted securely on a post or wall, facing southeast to catch the morning sun and warm the bees.
Within the shelter, the bees require specific nesting materials that mimic the natural hollow reeds or wood tunnels they seek. The two most common options are reusable wood trays, which separate into grooves for easy cleaning, or disposable, paper-lined cardboard nesting tubes. These tubes should have an internal diameter of approximately 6 to 8 millimeters, the preferred size for Osmia species.
A reliable source of moist, clay-rich mud is a requirement, located within 25 feet of the nesting site. The female mason bee requires this mud to construct the cell walls and cap the end of the nesting tunnel after laying her eggs. If natural clay soil is unavailable, a small container of moist, untreated clay soil should be provided and kept consistently wet for easy collection by the bees.
Receiving and Handling Your Bees
Upon receiving the shipment, immediately inspect the package to ensure the cocoons are intact and the temperature inside the box is cool. If the local weather is not yet consistently warm enough for emergence, temporary storage is necessary to keep the bees dormant. Dormancy is maintained by placing the cocoons in a clean, airtight container inside a refrigerator, ideally around 34–38°F (1–3°C).
The cocoons should only be moved to the nesting habitat when local flowers begin to bloom and the weather is reliably mild. The most effective release method involves placing the cocoons into a small, dark release box positioned directly inside or adjacent to the prepared nesting house. The emerging bees will instinctively fly toward the light and discover the nearby nesting tubes.
It is important to avoid scattering the cocoons or placing them directly into the nesting tubes, which exposes them to predators or moisture. Using a dedicated release container ensures the bees are protected until they naturally emerge and begin their reproductive cycle.