What is this pale mint green shrub that has hay-colored booms? It seems to thrive on lava fields and develops lignified stems.
EDIT: With the plant having been identified below as Erysimum scoparium, I have to add that the following pictures were taken on 2016-11-06 (i.e. November). There was no florescence, so the plants lacked their mauve, pale purple blossoms (see Commons gallery).