A question I regularly get asked is 'what can I grow in shade for bees'. Allowing for the fact that bees would generally prefer to forage in sun - to avoid their small bodies cooling down - there are some plants that will be happy in shade but still provide value to bees.
Of these plants, the one I find most effective is geranium phaeum, otherwise known as 'dusky cranes-bill' or the very evocative 'mourning widow'.
It is happiest in dappled shade which replicates the edge of woodland and produces a nice mound of foliage often with attractive dark markings. The foliage spreads up to 50cm across from March right through to October, making it a good groundcover plant.
The flowers arrive as soon as spring begins to warm up and will continue flowering until the end of June; if find that if you cut off finished stems you sometimes get a second batch.
The range of flowers for this plant can be from white, through purple to a very dark maroon which I believe is the 'native' version. In the right conditions they can hybridise and self seed; the one I do at rosybee has evolved from my garden and is a mix of the dark purple 'lily lovell' and a white one which have resulted in a purple flower with a white centre......delicate but stunning.
The reason I think this is a candidate for 'best shade plant for bees' is that it is currently the highest ranking shade plant in our research and this year sits in 31st place (just outside the top 30) and far above other shade plants. It attracts mainly carder bumblebees - which are themselves quite tolerant to shade - but also a range of other bumblebees.