I’m sure there are better
native bee experts out there than I and I’d love to hear what they think. I think that the keys are to not use treated wood, use
local sourced hollow stemmed plants, make sure that the cavities are as deep as possible, the opposite end needs to be plugged. Then remember that many native
bees are ground nesters too, so bare soil that is well drained is important too.
https://www.xerces.org/ Has lots of good info.