Mining bees vs mason bees
The two solitary bee groups most people actually encounter — one making small volcano-like mounds in a lawn, the other filling bee hotel tubes with mud.
Which to choose
Not a choice — encourage both, and the methods do not overlap. For mining bees, leave a patch of bare sunny soil and do not treat lawn mounds as a problem. For mason bees, put up a bee hotel with tubes from 4 to 10 mm, site it facing south-east, and make sure there is mud within reach. If you have fruit trees, the mason bee tubes will pay for themselves in fruit set.
Why these get compared
Both are common in gardens, both are frequently reported as problems, and neither is one. Telling them apart explains what is happening in each case.
Where they differ
| Axis | Mining bees | Mason bees | Why it matters |
|---|---|---|---|
| Nesting | Excavate burrows in soil, leaving small mounds | Use existing cavities and seal them with mud or leaf paste | The mounds in a lawn are mining bees. The sealed tubes in a bee hotel are mason bees. |
| Group size | Around 1,500 Andrena species worldwide | Around 500 Osmia species | Mining bees are the larger and more varied group. |
| Pollen carrying | Brushes on the hind legs | Brushes on the underside of the abdomen | A mason bee returning with pollen looks orange underneath, which is the quickest field distinction. |
| Season | Spring, mostly March to June | Spring, March to June | They overlap almost exactly, which is part of the confusion. |
| Garden value | Excellent early pollinators of fruit blossom | Outstanding — several times a honey bee per individual on orchard fruit | Mason bees are managed commercially for orchard pollination; mining bees are not, because they cannot be housed. |
| Can you help them | Leave bare sunny soil undisturbed | Provide 6-10 mm tubes and damp clay within 50 m | The intervention is completely different for each, which is why generic advice fails. |
Where the difference is overstated
That either is a threat. Mining bee mounds do no damage to a lawn and wash away within weeks; mason bees are so mild that they are handled without protection commercially.
Sources
- Field Guide to the Bees of Great Britain and Ireland — Bloomsbury (2015) · Field guide
- Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic review Link
How sources are selected and weighted is set out in the sources and evidence policy.