Hydrangeas like a moist soil. Lavenders would like the open dry aspect and phlomis I believe would be OK though I've never grown it. I've seen cistus growing on sand dunes and it survives on top of a dry bank in my garden. Rosemary likes dry well drained ground. euonymust fortunii comes in several varieties and is evergreen. It will make a spreading shrub that would be very crawl-underable. None of these grow anything like as high as hydrangeas though. How about some of the taller grasses There's an area of different tall ones by the pool at Kew and they look great, some listed on the site below.

http://www.thompson-morgan.com/plants-for-dry-sunny-borders : this page has a list of more shrubs that might please you. Not recommending the supplier but the info is useful. You'll need to copy and paste as links don't seem to work on this site.