I should have clearer with what I meant by "probably". Your pictures are excellent, June, and provide more than enough information to make the ID. EXCEPT for the fact that most species of perennial sunflowers in North America exhibit a great deal of variability within species and a considerable amount of overlap between species. It's often all but impossible to identify them with 100% certainty just by looking at them.
That said, your plants look like Helianthus grosseserratus to me. That's probably what they are.
