There was a blog about them some time ago - put long flowering perennials into the search box.

Thanks..will do.

Penstemon, can't beat them, I had some flowering until Christmas.

My recommendation would be Hyssop which can be seen in my photo section. (Page 5- photo 100-2115 just to the left of the frog conga line photo) But...this very fragrant plant is a great attractor of pollinators of every sort including hummingbird moths and keeps them very busy so there is no chance of being stung by an armed pollinator if that's what concerns you. Mine flowers all summer long and well into late October. Full sun to partial shade and the border you see in the photo is growing in heavy clay soil so it's not fussy about what it has it's roots in. Also the Hyssop you see in the photo is in its second year of growth and about five feet in height. I planted four pots the previous year and their height then was just about two feet. It filled out nicely and unexpectedly quickly.

Helenium, Rudbeckia, Echinacea, Lychnis coronaria, Penstemon, Phlox paniculata, Coreopsis, Phygelius, Geraniums, Kniphofia.....to name but a few long flowering, hardy, easy to grow perennials.

Osteospermum are only semi hardy but flower their socks off.....

There are a couple of fully hardy varieties, Pam.

They don't get as tall as persicarias though - is there a pink hardy one?
I agree with Lizzie, Penstemons are hard to beat for flowering time and although they don't spread much cuttings are easy to root.

Is there Badfish? Would they survive in pots do you think...those in the cold gh look ok but it will be interesting to see if those on the patio survive the snow and frost we have
I think the rabbits have pruned my heuchera again ?