"I Went to Disneyland!"

...said the leaf-cutter bee.

And from the looks of things, he had a very good time.

Evidence of leaf-cutter bees on my Rosa 'Disneyland'

Rosa 'Disneyland'

Leaf-cutter bees (Megachile rotundata), a.k.a. alfalfa bees, like to use rose leaves to line their nests. They don't manufacture honey or form colonies like honeybees, instead preferring to raise their young in solitary nests. 

They rarely cause more than cosmetic damage to rose bushes or their other favorites - green ash and lilacs. I also noticed they like the leaves of our green bean plants. Sometimes they'll bore into the soft wood of cut rose canes, so to prevent them setting up housekeeping there, you can put white glue on the ends of the canes after pruning.

Leaf-cutter bee
Photo by Jodelet/Lépinay - Wikimedia Commons

The adult lives about two months, and is most active during the time alfalfa is in bloom. They never become a problem and because of their value as pollinators - they're much more productive than honeybees - insecticides are not recommended, nor are they particularly effective. The females can sting, but they rarely do so. Both males and females bite as a method of defense, but won't, unless squeezed or otherwise provoked. They do have natural enemies - parasitic bees and wasps, velvet ants, and certain blister beetles.

Here's a video that I found on YouTube of a leaf-cutter bee in action:

Have you noticed the leaf-cutter bees on anything in your gardens? If so, what are they choosing to take back to their nests?