If there are wild mason bees in your area, you might as well try to "capture" some of them. What's to lose? Go ahead and put out whatever nesting materials you have and see what happens. Mason bees use several nesting sites during the season and are intermittently on the lookout for new homes. They fill one up and need another. I say go for it.

While you can't get any live bees at this point, there's still time to trap-nest some.

Put a houe out if you have one (sunny location). If looks don't count, you might try making some of the cheap-and-easy styles of mason bee homes, like a cardboard box packed full of paper straws, and put them in several locations (even in the wild if you can.)

Those are very poor systems for long-term husbandry and parasite control but what the heck, try as many places as you can to increase your odds.

Kinsman Gardens makes some kits that are around $12 each. Poor design for long-term management, but cheap and easy for a hail-mary throw. :-)