The most sun tolerant hydrangeas are hydrangea paniculatas but, you and I where the summer sun is so hot that the leaves sometimes get sun scorch. Compact paniculatas like Bobo, Little Quickfire and Little Lime may be needed in that area but again, you may have to "test the waters" first with just one such shrub. That way you can transplant to another shadier afternoon location if the first location is too sunny.
Since these are deciduous plants, I wonder if you might prefer to use compact shrubs like Japanese boxwoods. Some of those are cheap, not thirsty like hydrangeas and will not care much about the amt of sun that you describe. By the way, hydrangeas prefer morning sun and afternoon/evening shade. Or dappled sun. Except for paniculatas, which like more sun and can be planted in full sun up in the northern states. Paniculatas can be large shrubs so make sure you select compact ones like Bobo, Little Lime, Little QF, etc.
Last edited by luis_pr
on Fri Apr 21, 2017 12:28 am, edited 1 time in total.