Geranium Phaeum or, in the wild, Dusky Cranesbill is the best early, easy-to-grow and beautiful plant for bees that I know of, particularly happy in dry or damp shade, I was watching up to ten Bumblebees and some Honeybees feeding on this one plant in the garden yesterday. Garden varieties extend the native, deep maroon flowers through pale mauve to white. All hardy geraniums are good for insects but Phaeum is early and can be cut back to reflower later, or left to provide seed for finches.
Conditions: Cloudy and some rain. Temperature: Max 12- Min 9 c.