It’s easy enough to say “Plant flowers” for the bees, until you ask which flowers? If I had to pick one to start with, I would say Purple Coneflower. Bumblebees and honeybees love it. Other native bees, too. As a bonus, the seeds will feed goldfinches. But then, they’re coming into their full color right now, so maybe that’s why they leap to mind.
If you want more, there are places you can look up lists of suggested plants to attract bees and other pollinators. Mostly I looked at what was drawing bees, both in my yard and in the nursery.
So the list I started last year is now:
April: Grape Hyacinth
April: Plum and other fruit trees
May-August: Red, black, and fall-bearing Raspberries
July- frost: Butterfly bush
May – Sep: Snapdragons
Summer: Squash, pumpkin, melon (Squash bees)
Suptember: Sedum (I see I need to get a picture this year!)
Feed the bees!