If you are interested in promoting pollen bees in general, you want to have a variety of plants blooming in your garden all season, to maintain a wide diversity of spring, summer, and early fall bee species. This usually means that the plant has been selected to develop extra petals instead of anthers. So there will be little or no pollen available for bees. All bees need pollen as food for their offspring, and will not be attracted to double flowers unless they happen to produce lots of nectar. Marigolds, mums, many roses, etc. will attract few bees species unless you plant the single varieties.
Bees tend to be attracted especially to flowers that are blue, purple, and yellow.
Many hummingbird pollinated flowers have evolved to be red in color They also tend to have deep tubes. Butterflies may also be attracted to such flowers. Hawkmoths also like deep-tubed white flowers, that produce scent at night. Bees generally don't visit such flowers, although there are exceptions. Flowers with short tubes or no tubes are more likely to attract a variety of bees.