depends on how severe your winters are. If it's anything like New York, bring them in.

heathers will cope with most extremes of conditions in this country so I would say that they will be OK. Perhaps, give them a light prune in the spring to prevent them getting too straggly.

I agree with Jimmy, our native heathers cope with the wilds of Scotland and wales so they will be fine in the ground. if they are in ornamental pots then you may have to consider moving them closer to a wall when severe frosts are forecast.

If you expect a deep freeze, they'll need protection such as a fleece or drop cloth. If in pots, move to a sheltered location or just move them into the green house for the winter. That's what it's for.

Bathgate's advice applies to hard American winters. Hardy heathers in this country normally need no protection in the ground - but unsure what you mean by ornamental ones?
Do you have the plant labels that tell you what the varieties are? Heather does grow wild in Northumberland as the others have said..
(Assuming you don't mean the ones that have been sprayed in un-natural colours like blue...they will soon die anyway.)