Ground bees, often called mining bees or digger bees, are common in lawns and gardens, especially during the spring. Their nesting activity in the soil can cause concern for homeowners who may confuse them with aggressive social wasps. These solitary native bees play a largely misunderstood role in the residential ecosystem. Their presence is generally an indication of a healthy environment.
Identifying Solitary Ground Bees
Ground bees seen in yards are typically solitary species; each female digs and provisions her own nest independently, unlike cooperative colonies of honeybees or wasps. These bees are small to medium-sized, usually brown, black, or slightly metallic, ranging from a quarter-inch to three-quarters of an inch long. A distinguishing characteristic of their presence is the small, volcano-shaped mound of soil, known as a tumulus, surrounding a pencil-sized hole.
They prefer to nest in sunny, sparsely vegetated areas with dry, well-drained soil, such as bare patches in a lawn or along a path. Although many nests may appear close together in a favorable location, this is an aggregation of individual nests, not a communal colony. The female ground bee is non-aggressive and will rarely sting unless severely provoked or accidentally stepped on.
Essential Role in Local Pollination
Ground bees are among the earliest native pollinators to emerge in the springtime, often becoming active before honeybees and many bumblebee workers. This early emergence makes them essential for the fertilization of early-blooming plants and fruit trees that flower when temperatures are still cool. Their ability to forage in cooler, cloudier conditions makes them reliable pollinators when other bee species are less active.
They are highly efficient pollinators, collecting pollen on specialized hairs to provision the brood cells in their underground nests. Some species specialize in collecting pollen from a limited number of plant species, ensuring targeted cross-pollination. Ground bees support the production of various crops, including early-season fruits like apples, cherries, plums, and blueberries. Their activity contributes to the health and diversity of the local ecosystem.
Managing Nests in Residential Areas
Since ground bees are beneficial pollinators and pose a minimal stinging threat, the recommended approach is tolerance or non-lethal management. Their active period above ground is relatively short, usually lasting only a few weeks in the early spring. Homeowners can encourage these bees to relocate without resorting to harmful chemical treatments.
To make the soil less appealing for nesting, increase the moisture level in the area where they are digging. Ground bees prefer dry, bare, or sandy soil, so regularly watering the site can persuade them to move their activity elsewhere. Planting ground cover or applying a layer of mulch or gravel over bare patches of soil will also deter them from establishing new burrows.
If nests are located in a high-traffic area, they can be temporarily covered with a heavy object like a brick or landscape fabric to block the entrance. Using natural deterrents such as sprinkling ground cinnamon or applying a mixture of water and vinegar around the nest area may also make the location less desirable.