Mining bees (Andrena) are solitary, ground-nesting insects that often cause concern for property owners in the spring due to their burrowing activity in lawns and gardens. Because they are valuable pollinators and their presence is temporary, a safe, non-lethal approach to management is preferable. Understanding their life cycle and habits is important for effective and responsible management. This guide provides practical methods for encouraging them to relocate without causing harm.
Identifying Mining Bees and Their Activity
Mining bees are typically small to medium (0.3 to 0.7 inches), moderately hairy, and black or dull metallic in color. Females often possess velvety depressions, known as facial foveae, located between their compound eyes and antennae. Andrena are solitary, meaning each female builds and provisions her own nest, though they often nest in large, close aggregations.
They are among the earliest native bees to emerge, typically active for only a few weeks in the early spring, usually between March and May. Females excavate individual tunnels in the soil, easily identified by the small, volcano-shaped mound of loose dirt surrounding a pencil-sized entrance hole. These burrows are most commonly found in areas with dry, sandy, or well-drained soil that has sparse vegetation.
Despite the activity around the nest entrances, mining bees are exceptionally docile and non-aggressive, rarely stinging unless crushed or handled. They are valuable pollinators for early-blooming plants and fruit trees. The adult bees naturally complete their life cycle and disappear before summer begins, with the next generation remaining underground until the following spring.
Safe and Effective Deterrence Strategies
The most effective approach to managing mining bees involves modifying the environment to make the area unattractive for nesting. Since these bees prefer dry, exposed soil, altering the moisture content of the ground is a primary deterrent. Consistently and thoroughly soaking the nesting area with water for several days during their active period will discourage the females from establishing burrows. This should be done in the late evening when the bees are less active.
Covering the bare ground they seek for nesting is another powerful, non-lethal strategy. Applying a thick layer of mulch, compost, or gravel to garden beds and flower borders prevents the bees from accessing the exposed soil surface. For areas with sparse turf, maintaining a healthy, dense lawn through regular fertilization and re-seeding will naturally deter them. A thick canopy of grass makes it structurally difficult for the female bee to dig a tunnel.
Physical barriers can be deployed during the brief nesting season to prevent females from entering the ground. Fine mesh netting or landscape fabric can be temporarily secured over the affected area for the few weeks they are active in the spring. Strong natural scents can also be applied to the soil surface to create an unfavorable environment. Sprinkling ground cinnamon or applying solutions containing essential oils like peppermint or eucalyptus around the nest entrances may encourage the bees to relocate.
Direct Removal and When to Call a Professional
For property owners who cannot wait for the bees to complete their brief spring cycle, direct intervention requires careful timing. The simplest active measure is to wait until the adult bees are no longer seen (usually by late spring or early summer) and then fill in the empty nest holes. Sealing the holes while adults are active or young are developing should be avoided, as this can trap them and potentially lead to them digging new exit tunnels.
Immediate, targeted interventions exist, but they must be approached with caution due to the bees’ beneficial nature. Applying a dusting of Diatomaceous Earth (DE) around the nest entrances can act as a physical deterrent, discouraging the bees from re-entering the burrow. While a mild solution of dish soap and water poured into the burrow is sometimes suggested, this method is lethal as the soap disrupts the bee’s protective outer layer, and is generally not recommended.
A professional should be contacted if the population is extremely dense and environmental modifications have not been successful in deterring them. Calling an expert is particularly important if a member of the household has a known severe allergy to bee stings. Specialists can provide species identification to ensure the insects are docile mining bees and not a more aggressive species like yellow jackets. Experts also possess the knowledge and equipment to manage the situation safely, sometimes offering relocation services or targeted treatments when non-lethal options are exhausted.