Mark, it looks like a hairy plant, so it could be H. tomentosum from the S. Europe.
Initially I thought it might be H. tomentosum, but then the habit in flower doesn't match what I grow under that name, although I admit that I have never tried to verify that what I'm growing is true tomentosum. I find Hypericum to be another difficult genus to key, as there are species throughout the globe, and no good single reference (that I know of) on the genus.
My "H. tomentosum" starts out with basal shoots, rather fuzzy and whitish-green, but these grow upright to 1-2' (30-60 cm) and have very small flowers, Mark's plant looks like a much nicer rock garden worthy Hypericum.
Reginald Farrer in The English Rock Garden writes about H. tomentosum: "a woody plant with many flopping stalks clothed in oval foliage that in its turn is clothed with fluffy down or wool. It is not a common speciesm being found here and there in the warmer parts of South and Central Spain; with two varieties, H. t. dissitiflorum and H. t. intermedium."
H. tomentosum might be described compartively against a related new species here, but this is a "pay for publictaion" link.
http://onlinelibrary.wiley.com/doi/10.1111/j.1756-1051.2009.00736.x/fullAnd found a few photo links of tomentosum, again, I can't vouch for species ID authenticity, but the following two look similar to what I grow. The flowers are rather small.
http://www.flickr.com/photos/58237382@N00/3637741591/http://www.flickr.com/photos/58237382@N00/3637741329/in/photostream/...more:
http://www.flickr.com/photos/marialuisa/4693716121/http://www.flickr.com/photos/salvador_tello/4380773663/
