Any ideas regarding the identity of this hardy orchid which I found blooming in a great swath at the base of a driveway in the Blackridge subdivision in Pittsburgh last week? I've noticed the plants in this yard every summer while visiting our family, but prior visits have never coincided with the bloom period. I even went so far as to ring the doorbell (a great step for a shy person), since the garden in general was really interesting and well-kept, but there was no answer.
My best guess, based on research, is Epipactis palustris, a European species. I've grown E. gigantea, but it has fewer, larger flowers spaced farther apart on the stem, and is also more of a reddish-brown tone. I'm assuming it isn't a species native to the area, since I didn't see it growing anywhere else except in this yard.
Anyone want to weigh in with an identification?