It is drought tolerant -like all the other oakleaf hydrangeas- once established but does not like its feet (roots) to get wet. If they get wet for too long, it will catch root rot... like all other oakleaf hydrangeas. So do not pick locations with standing water. I have Ruby Slippers and yours is somewhat similar in dimensions. They are deciduous most of the time for me (evergreen in some years) but that will not happen in a Z5 winter. Low growing shrubbery (hostas, etc) and yellow leaf shrubs (for contrast) would look good. I too have all my oakleaf hydrangeas in full shade but bright/indirect sun. No problems bloomage-wise. The stems & flower buds have withstood overnight temps of 13F/15F for me but I am in Z7b/8a. They were developed in Tenn and tested in various other locations. The Missouri Botanical Gardens like them so give them a try. They do bloom on old wood. They have resisted by area's tendency to zoom temps to the 80s and then crash to the 20s without winter protection. But you have much different weather; it mostly stays cold for you and my dips below freezing last a little more than a week.

Here is reading material on Munchkin and Ruby Slippers... both were released at the same time by the Natl Arboretum:

http://hortsci.ashspublications.org/content/45/12/1908.full

http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=d380

Awesome $10.... For that much, I would give it a try and report how it goes once they have become established. Mind you, that $10 price is awesome. I have seen 25-33% discounts in the last few days with hydrangeas but I am still paying in the upper 20s to mid 30s..

What a deal! In zone 5b you can give it some sun, and it will have better fall color, one of the nice things about oak leaf hydrangeas.

I know - the price was SO right! All of the Home Depot flowering shrubs were on sale 50%. I also bought a good size pot of "Bobo" hydrangea for $12! It was just my lucky day. I'm off this week on vacation and couldn't resist a trip to HD. :-)

Thank you both for the info on the oak leaf hydrangea. I was wondering also if a Western exposure would be ok?

No, while they are more drought tolerant, only paniculata leaves are thaaat sun tolerant. Maybe the Annabelles come next. I have all of my oakleaf hydrangeas in morning sun, dappled sun and in full but bright shade. But since your sun is weaker, you could try "testing the waters" while the oakleaf is potted. It is way easier to move it to a more shaded location while potted than while planted on the ground.

I don't find this plant - or any other hydrangea - to be very drought tolerant at all. Consistently moist (not wet) soils are best. Location will play a big role in siting but these thrive happily in full sun here in the PNW and develop their best flowers and fall color if given substantial direct sun. Even my 'Little Honey' is in almost full sun and never scorches or displays signs of sunburn. If grown in more shade, the leaves tend to be larger but the shrub is less inclined to flower heavily or develop strong fall color. The very heavy texture of the leaves on oakleafs increases sun tolerance but in the South (luis' location) or in hot summer areas, some protection from late afternoon sun is advised.

Thanks everyone for the advice. I've decided to plant my oakleaf hydrangea in the Fall on the East side of our garden. Both the "Munchkin" and "Bobo" hydrangeas are 2G sizes.