Pest Control
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Small mounds of fine soil, each with a neat hole in the top, appearing across a lawn or bare border in spring are usually the work of mining bees. They can look like an infestation. They are not, and the best thing to do is leave them alone.
What are mining bees?
Mining bees are a large group of solitary bees, many of them in the genus Andrena. The one most people notice is the tawny mining bee, a fluffy, ginger-orange bee seen on lawns from around March to May. Unlike honeybees and bumblebees, mining bees do not live in colonies. Each female digs her own short burrow, stocks a few cells with pollen and nectar, lays an egg in each, and seals them.
The young develop underground through the summer and winter, and emerge as adults the following spring. That is why the same patch of lawn tends to see them year after year.
How to recognise them
- The mounds. Small, volcano-shaped heaps of loose, fine soil, a few centimetres across, with a hole in the middle. They often appear in groups on lawns, bare soil and banks.
- The bees. Bees flying low over the ground and disappearing into the holes on warm, sunny days.
- The timing. Early to late spring. By early summer the activity has stopped.
Ants also leave small heaps of soil, but ant mounds are flatter and the ants stay on the ground. Our bee identification guide covers the other bees you are likely to see.
Are they dangerous?
No. Male bees of any species cannot sting. Female mining bees can, but they are not aggressive, have no colony to defend, and very rarely sting even when handled. Children and pets can play on a lawn with mining bees nesting in it.
Do they damage the lawn?
Not in any lasting way. The mounds can look untidy for a few weeks. Once the bees have finished, the soil can be brushed back into the lawn, and the grass recovers. There is no damage to roots or turf of the kind that chafer grubs or leatherjackets cause.
Why leave them alone?
Mining bees are among the first bees out in spring, and they are useful pollinators of early flowers and fruit trees. Nests are scattered and short-lived, so treating them would mean applying insecticide across a lawn for something that is finished within weeks. We do not recommend it.
If the mounds bother you:
- Brush them back into the grass with a stiff broom once the soil is dry.
- Hold off mowing very closely or scarifying the busiest patch until early summer.
- Accept that they will probably be back next spring, for a few weeks.
When to call us
If you are not sure whether you have mining bees, ants or wasps, send us a photo of the insects and the mounds. We will tell you what they are, and with mining bees, our advice will be to leave them. Our bees page explains how we approach bees more generally, or call 01926 632 929.