Echinaceas are fully hardy so it should be fine. If they die in winter it's usually because they are planted in badly drained clay soil that gets too wet. If you are worried you could always wrap the pot in fleece or bubble wrap.
I can't keep these going. I put them in the ground, might get a poor flower or two in the first year and never see them again. I haven't got particularly heavy soil. Could dryness through the summer be a problem? I planted yet another one in September and it looks good and leafy at the moment. It would be good to see some flowers like the ones I see in other gardens. Any suggestions as to how I might look after it better?
I have kept mine in the conservatory ,seems to like that.
Another reason that echinacea disappear is that slugs love them.
I'll go and dig it up.
My greenhouse isn't heated, will it be OK or should I wtap it up as well?