Leafcutter bee house: the right tunnels for Megachile, June to August

At a glance: leafcutter bees and their houses

• Fly June to August in the UK — later than red mason bees.
• Need tunnels around 6–7mm in diameter, 10–15cm deep, sealed at the back.
• Build cells from cut leaf discs, not mud.
• Non-aggressive solitary bees — no hive, no queen, no colony to defend.
• Favour roses, lilac, wisteria and Virginia creeper as leaf sources.

Anyone who's spotted perfectly round or oval notches cut from garden leaves has usually met a leafcutter bee's handiwork before ever seeing the bee itself. Getting a leafcutter house right is a slightly different job from a general bee hotel, because the species has its own timing, its own preferred diameter, and its own construction material.

Why 6–7mm matters specifically for leafcutters

UK leafcutter species (genus Megachile) are generally a size class smaller than red mason bees, and tunnel diameter needs to match a female's body width closely enough that she can pack material against the walls. Too wide and the leaf discs won't seal properly; too narrow and she can't fit at all. The reliable range is 6–7mm, distinct from the 8mm that suits mason bees — see our full diameter and depth chart for how every size in between gets used.

Why gardeners see the cut leaves before they see the bee

Leafcutter bees are fast, quiet workers and rarely settle long enough to be noticed mid-cut. What's far more visible is the aftermath: smooth-edged circles or ovals removed from leaf margins, usually from soft, pliable leaves like roses or lilac. A female can complete a cut in under a minute and fly the piece straight back to her tunnel, rolled lengthways in her legs and mandibles.

Leafcutter vs red mason bee nest construction

Common mistakes with leafcutter houses

• Offering only 8mm+ tunnels, which excludes leafcutters entirely.
• Siting the house somewhere with no leafy plants nearby to supply material.
• Unprotected entrances where rain soaks and unravels the leaf-disc plugs before they cure.
• Rough-sawn tunnel rims, which shred a leafcutter's wings faster than a mason bee's, since she's carrying bulkier material through the same gap.

Season by season

Spring is quiet for leafcutters even while mason bees are active in the same block. Activity picks up through June, peaks in July, and tapers by late August. The sealed tunnels then sit through autumn and winter exactly as described in our guide to how a bee house works, with adults emerging the following summer rather than the following spring.

What to look for when buying a leafcutter-friendly house

• A genuine spread of diameters including 6–7mm, not just 8mm.
• Depth of 10–15cm so a full clutch of cells can be laid.
• A roof that keeps rain off the leaf-disc plugs while they cure.
• Sanded, splinter-free tunnel rims that don't shred wings on entry.
• A sealed rear panel, exactly as required for any solitary bee species.

The Wild Bee Hotel's tiered tunnels cover this whole range in one block, so the same house that hosts red mason bees in spring can host leafcutters through the summer without any changes needed.