A big thank you to Jan Miller Klein for her talk on February 4th based on her book: Gardening for Butterflies and Bees and other Beneficial Insects. Jan pointed out that as the countryside and hedgerows become more cultivated it is wild spaces, such as neglected brownfield sites which now provide the safest and most abundant source of food for our native butterflies and bees. Many butterflies only lay their eggs on specific plants so if we can introduce some of those to our gardens we can do our bit to promote biodiversity! Whilst this list is not complete I did jot down some of the plants she recommended for different seasons, many are wildflowers:
Spring
Honesty, Aubretia, Forget-me-not, Wallflowers (perennial), Willows, Jack-By-The-Hedge (garlic mustard), Lady’s Smock (Cuckoo Flower) and other 4 petal flowers.
Summer
Scabious, Bird’s-Foot-Trefoil (yellow), Red Clover, Lavender, Runner Beans, Viper’s Bugloss.
Late summer/Autumn
Hebe (old varieties such as Midsummer Beauty, Great Orme), Sedum (spactabile), Michaelmas Daisy (old varieties), Thistles, Teasels, Knapweed.
Winter
Ivy – left to flower and flourish provides essential nutrients for bees.
And for those of us planning a green roof she recommends looking up Dusty Gedge and John Little.
De Beauvoir Gardeners 
Sounds as if I shouldn’t eradicate the old Michaelmas daisies I inherited with this garden, but try to grow them where they won’t stifle more valued plants. And I’ll take any excuse to keep propagating the almost equally old sedum spectabile I found at my first flat. I’ve grown both in sizeable pots, although the sedum looks happier in that environment.