The teucrium family has hundreds of species but for some strange reason you rarely see them in Garden Centres. I know people with the subshrub types that observe they attract large numbers of bees and I certainly find its true for the herbaceous version we grow: teucrium hircanicum.
Its a really well behaved perennial that gently clumps up without trying to take over the border, sets the odd seedling but without scattering them as weeds and - a big deal this year - seems to be resistant to slugs as well as cold, damp and dry conditions.
At rosybee its just beginning to flower now, at the end of June, and will keep providing its dark pink spires right through to September.
In our research it ranks 9th out of the 80 plants we have tested so far, attracting mainly honey bees but also bumblebees and butterflies. Because its flower are arranged in spires with a 'tier' of buds opening each day or so, the bees tend to land and then do a circuit round the spire. This means you get a really good look at them too.