Hoary Stock.

Another from my 'Flowers In The Kitchen' series!

Matthiola incana, also known as hoary or tenweeks stock, is a species of flowering plant in the genus Matthiola. It is a common garden flower, available in a variety of colours, many of which are heavily scented and also used in floristry.

Interesting side note: when looking it up online I found a listing in The Jepson Manual (Vascular Plants of California, Thoroughly Revised and Expanded)