Leafcutter Bee Nesting Material

I have extensively read this forum searching for which plants would be best to use for nesting material for leafcutter/mason bees but have only come across a reference to giant parsely and reeds. Which plants are used for this nesting material as I would like to acquire some.

I have noticed 40-60 female leafcutters visiting my woodpile so I made 6 nesting blocks (5/16" dados for tunnels) and none of the girls seem to want to visit the blocks. I have the blocks covered with some aged firewood for protection from the elements but I have not had one taker in over a week. There are three 40 acre plots of alfalfa within 500-600 feet of my woodpile so I was wondering what an optimal location would be for the blocks (closer to the fields) or possibly try to cover the woodpile so the blocks become more appealing?

My main interests are what plants can be used for nesting material and where the best placement would be for the blocks.

I just bought some leafcutterbee-specific nesting tubes from Dave at crownbees.com ...he now carries the cardboard nesting straws that are narrower, for summer and leafcutter bees. I think he sells cocoons too if you want to get a head start. He might give you some good suggestions as to nest placement as well.

I think your tubes are a hair to large. Might want to try 1/4".

When I trimm back my rose bushes I trim the canes to 7" and jam a 1/4" rod down the pith and leave them in stacks around the yards. Something is filling them.