You may find this blog useful

http://www.growsonyou.com/anchorman/blog/12681-plants-with-a-very-long-flowering-season

Hello and welcome to goy NG a nice corner to enjoy with a real splash of ever changing colour through the seasons.

Hope you have planted snowdrops and other spring bulbs.

Heucheras ,lavendars. a buddliea rhodendrums daphene could go on .

But will let others add.

Helenium 'Sahin's early flowerer' is a good yellow/bronze flowered plant and starts may and as we speak it is still in flower. Japanese anenomes, alstromeria, day lilies are all good plants.

Rudbeckias, hardy fuchsias and penstemmon are my 3 favourite easy care very long flowering season plants ( July to November

I would always recommend hardy geraniums I tend to go for the ones that flower all summer, lots of colours and height to choose from, and they make great ground cover.and the slugs and snails don,t like them,