Cistus × purpureus (Cultivated- USA)

Cistus × purpureus Lam., Encycl. 2: 14 1786. (Syn: Cistus × purpureus var. argenteus Demoly);
Garden Flower For ID : California : 09NOV14 : AK-20 : 9 posts by 4 authors. Attachments (1)
Cultivated, garden flower seen in San Francisco on the 1st of October.
Single pink flower.
do you have the mound of it or was it a hedge?
i would like to see the habit of this plant
This was a small patch of garden plants as far as I can remember, definitely not a hedge.
In the garden at the Golden Gate Viewpoint. 
pink rock rose
the tell tell sign is the small patch of brown or scarlet in lighter colors pink of what should be five petals... this flower seems to be in the process of dropping the petals
rock rose so cistus
species  may be any body's guess as it stands with one photo. 
if i were to be forced i might say cystis purpureus but i wont stick my neck out for one half way dropping off flower.
Your sharp eyes could spot the signs.
I have cropped my picture so the small brown patches on the petals are visible.
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I hope yes Cistus purpureus
Thank you so much for the id.