What's in a bee-friendly garden?

After a few fairly technical posts lately (taxonomy and the like), I thought it was time for something a little less cerebral i.e. watching bees and seeing which garden plants are important food sources in spring.

I've seen a few bee species already this year (inlcuding a few yet to be identified), but one that has stood out by spending a lot of time in our garden is the Hairy-footed Flower Bee Anthophora plumipes. Being about the size of a bumblebee, these are quite distinctive and show considerable sexual dimorphism. The males have yellowish-brown hairs and a pale yellow face, while the females are black apart from orange hind femora (which can be hidden). Since a single male appeared on 13th March, I've seen the level of activity increase, firstly with the arrival of a second male and then a couple of females. Most of their feeding has been on Lungwort - they have been seen investigating other flowers such as the ornamental Quince, but this does not seem popular and is regularly spurned. I wondered if it was a nectar-poor cultivar, but today I saw a different bee species (maybe an Osmia) feeding from it. Hopefully I'll be able to add more species photos, but they don't stay still for long...

A. plumipes male on Lungwort

A. plumipes female approaching Lungwort - mmmm, tasty...

 Curious to know what other plants are important (to make sure the garden is bee-friendly), I tracked a few individuals and found a female actively investigating our small clump of Snakeshead Fritillaries. Only one is fully open and she spent some time in this flower before trying the other 'unripe' flowers and heading back to the Lungwort. All Fritillary pollination is welcome as the tiny clump is part of our 'wild meadow' area and it would be great if it could spread naturally.

A. plumipes female approaching Fritillary flower

Thinking about sorts of habitat beesd and other invertebrates require in a garden, I've been considering inlcuding a small bare sandy patch. It would be interesting to see if a sand-nesting wasp might appear, though I expect it'll be popular with the ants... However, bare soil - even in small patches - is used by all sorts of species, including the Andrena bee (possibly A. barbilabris, I'm not sure yet) below - seen investigating small bare patches on a south-facing bank in the local churchyard. These I believe are known to use compacted patches of soil such as on footpaths, and the bank is certainly quite well packed and warm. Along with the investigative behaviour, the amount of tussling between individuals suggested (to me at least) that either territories in the form of suitable soil patches were subject of competition, or possibly it was the locations of yet-to-emerge females (males emerge first). I'm hoping to get good shots of more species - hopefully identified - and come up with more ideas to attract pollinators, but until then, enjoy the photos so far!
 

Andrena sp. showing plenty of white fluff plus white bands on the abdomen.

Andrena sp. investigating bare soil - is that a burrow?