mason bees hive in my compost pile?

Asked April 19, 2019, 3:25 PM EDT

When i removed soil from my compost pile 30-40 bees came out. I believe they are masons. I had started artificial nests but they were not used last year. I don't want to destroy new eggs. Have they started laying by this time? I have a new pile started next to the old one. Can I take out old soil and hope they renest in pile next to it? I have tubes put out but they don't use them as a nest. The pictures show the artifical nest above the old compost pile on left and new on the right.

Clackamas County Oregon

2 Responses

Mason bees nest in hollow stems of plants. Do you have the appropriately sized stems in the compost pile? And have those stems been in the compost pile since last year at this time? If not, then the” bees” you saw could be yellowjackets, or another solitary native bee that makes a nest in the ground, or in this case, in a compost pile. Mason bees should have just recently hatched and still have a few weeks of egg laying left. You may use the old compost.

An Oregon State University Extension publication, Megachilid Bees in the Pacific Northwest contains information about mason bees and leaf-cutter bees. Another publication, Nurturing Mason Bees in Your Backyard in Western Oregon gives even more details specifically for mason bees. It outlines how to make your yard attractive to native mason bees by providing some bare soil, the nesting blocks, and many flowering plants.

It sounds like you are on the right track. Be patient, surely a wise mason bee will spot your nest tube and move in.

I was looking at some hollow tubes that come from my iris plants although a bit smaller than the commercial tubes i have used without continued success.

Definitely not yellow jackets or wasps. Maybe ground bees but glad that a similar pile and commercial tubes are present nerby.

Thank you very much