I planted a lot of broccoli this year and let some flower just for the bees. The broccoli always does well, but some of it always gets too far along before I pick it so I figured the bees will use it. They love it!
They also loved the corn pollen earlier this year. Even when there were other tasty flowers, they still went nuts in the corn.
They love turnip salad blooms probably mustard too. Turnip salad is one of the earliest sources of pollen too. That stuff was blooming middle/end of march here this spring.
Plant it now if you want it blooming next year. It produces loads of seeds and you can't kill the stuff. It'll be back year after year.
My old mentor always said he loved his honey unless they were growing broc/cauliflower around... cuz it took on that flavor of crucifers... kind of how you smell it when you're around the plants. I think they use sulphur compounds to attract flies as well for pollination.
I've also been wondering about the honey from all the garlic chives the bees are hitting up here. The chives are an invasive weed for me so there is a lot of them. The bees are crazy about them.
BTW, look at the tattered old wings and baldness of this old bee on this garlic chives flower. Poor old girl.
Oh yeah, she's worked hard for sure. I had one worse than that on my mint... I don't think she made it back though, I was amazed she could even get lift let alone fly. Allium sp put out a fair amount of nectar in general and you can definitely smell it for sure.