Anyone in the PNW have success with building a mason bee house? I just saw a filled in house in a new friend's garden. He made it out of bamboo. The bees had filled every tube, which were a variety of sizes. I looked online and read that the holes should be 5/16" but most of the bamboo were much larger in my friend's house. What experience do you have? What about location? Does north, south, east, or west facing make a difference?

I made one house by drilling holes in a block of wood and attached it to the south facing wall of my house about 5 feet off the ground. My friend mounted his close to the ground, east facing on the west side of his garden.

I also made 3 bumblebee houses and have set them out. I am hoping to encourage more pollinators as the honey bees are few in my area, especially when my cherry trees are blooming.

I did the same as you, drilled holes in a 4x4, attached to south facing wall at about 5', but didn't have good luck. I spoke with the mason bee folk at the NW Garden Show and they encouraged me to plant pieris near the house, which is one of the bees' earliest sources of food.

I also reached out to my local honey bee club to see if anyone was interested in setting up hives in my front field, but got no takers. I do have an offer from a friend's son who is a master bee keeper (whatever that might mean) and he is willing to give me a hive and some bees and instructions but he's about 8 hours away from me and I don't like honey and don't want to mess with the bees overmuch, just looking for pollinators.

Eye level. Facing easterly, they need the sun to warm they up, so they can fly. Also provide shelter from rain. Eggs and larvae will overwinter.
Lots of beneficials will use different size holes, from half inch to to eight inch. 😀👍
You can bring houses in garage to overwinter, if weather is to cold for them.
Happy Farming.
.😎😎😎

Our neighbor saved the hassle and rented some mason bees. Here's a couple of them on our anise hyssop.

How the heck do you 'rent' bees...??

Bonehead said:How the heck do you 'rent' bees...??

https://www.rentmasonbees.com

Jon55 said:
I also made 3 bumblebee houses and have set them out. I am hoping to encourage more pollinators as the honey bees are few in my area, especially when my cherry trees are blooming.

What design did you use? Did they move in?

Greg,
In addition to Pieris, you may want to consider some earlier bloomers such as Sarcococca (blooms Feb-March, with rebloom), along with Osmanthus & Viburnums. These were crucial to the Mason Bee population I had for many years, providing long-term foraging. The houses I had faced east & were sheltered.

Maukahound said:Greg,
In addition to Pieris, you may want to consider some earlier bloomers such as Sarcococca (blooms Feb-March, with rebloom), along with Osmanthus & Viburnums. These were crucial to the Mason Bee population I had for many years, providing long-term foraging. The houses I had faced east & were sheltered.

What variety of Sarcococca? I have Sarcococca hookeriana var. humilis, but I've never seen it bloom all the time I've had it.

Greg,
Any of the them as they all bloom sometime January to Late february, depending on your zone. If you hadn't seen it bloom, you may have smelled its soft sweet fragrance.
S.hookeriana is the shortest, spreads by runners.
S.ruscifolia - shrub to about 5' x 5'; red berries
S. confusa - shrub to about 3' x 5'; black berries.

I've grown all three & have found them to be excellent performers.
I think your S. hookeriana will grow better in the ground - they really like to send out runners. They are not in any way invasive, though. Mine slowly formed a nice 15-20' long"hedge" along a walkway.
I found them to perform better with part sun. They were all shaded from 11 - 2 or so from the sun, and got blasted from 3 until sunset. Moist rich soil with zero pests - a winner!

I've been wishing for a router, but Santa knows me too well. I'm on the wrong list!

Why I wish I had a router is two fold. One, if one routed out slabs, one could open up the mason bee house easier for cleaning, and the removal of any unwanted wasps larvae. And, two, I could put a bend in the tunnel. If you look at nature, the bees use tunnels made by other boring insects and those tunnels are not straight. Having a bend in the tunnel makes it harder for the wood peckers to reach in and pluck them out.

Just a thought.