Hi, Janie. Yes, I'm in the Great Lakes area. My yarrow is achillea millefolium Terra Cotta, and I dead-headed it last year (the first year I had it), but then I dead-headed everything. It grew tall and straight this summer, even after being transplanted in the spring. I guess it isn't too fussy about anything. I've been giving it a lot more water, because we've had a dry spell around here in July/Aug, although we had a wet May/June.

Maryanne