I have a Miss Canada in a row with two Miss Kim and one common (vulgaris) lilac. The common lilac gets powdery mildew every year (along with lots of other things including phlox and monarda) and this year was no exception. But the Miss Canada and Miss Kims have never gotten powdery mildew and they get more shade than is recommended. I have had them in place at least 7 years. I do water them during dry spells.

Thanks for sharing, chickadee. I wonder if part of my Miss C's problem is it is planted near a building so is blocked by wind from the north but is then exposed on the other three sides (the shrub is planted at the corner of the building) but anyway, I wonder if it just doesn't get enough air circulation where it is at...or I just got unlucky with mine!

I have lots of old garden phlox and all of it gets powdery mildew every year.

I just got one for my W Mass yard I hope it does better here. What is a good hardy blue variety?