Blue vervain, Verbena hastata
 
Impressive spikes of blue flowers bloom from July until September and attract bees, bumblebees and butterflies with their abundant amount of nectar.
 
Ecology:
Larval host to the Common Buckeye butterfly.
Seeds are a favourite food of songbirds.
Stems are used as nurseries by stem-nesting bees.
 
Growing conditions:
Blue vervain, also known as swamp vervain, grows in moist prairies, floodplains, and damp thickets in the wild. In the garden, it is an easy-to-grow plant that is not fussy about soil type. It will grow well in full to partial sun, average to moist, well-drained soil, and can tolerate occasional flooding. It is suited for rain gardens and around downspouts.